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Hi again, please see below for solutions and questions to this week's version of the POTW. Don't forget to check the solution that is posted, NOT JUST the answer!
Grade 7 POTW: This question is pretty simple: 40% of cars have 2 or more people, so the percentage of cars that contain only one person is 60%. Out of these people, 25% of them do not wear sunglasses. This means that 15% of the original 100% of cars contain 1 person who does not wear sunglasses. This means that 60-15, which gives me 45%, of cars contain 1 person who wears sunglasses. -Alan
Grade 7 POTW In order to find the answer to this POTW, I need to lay out the facts. 40% = 2 or more people, 25% of 1 person = sunglasses So now we're onto the math. With 40% of the cars containing 2 or more people, the other 60% therefore has to contain 1 person since it's on a highway. It can't contain 0 people obviously due to many cars being in a highway and there is no parking. The only exceptions are when something like a car accident happened, but we're just going to assume its 1 person because the odds are small and if that is the case then "more info needed". 60% of the cars have 1 person. Now, using the next piece of data, we can find out how many people are wearing sunglasses with 1 person in the car. 25% of 1 person in the car is wearing sunglasses. So in other words, 25% of 60% of 100% is a 1-person-glasses-wearer in the car. 60% of 100 is 60%. 25% of 60% is 60 divided by (100 divided by 25 (4)) which is 15. 15% of all the cars in the highway contain 1 person only wearing sunglasses.
so first I can eliminate the option that doesn't contain one person which is that 40% of the cars had 2 or more people. so I subtracted that with the total percent, 100 - 40 which got me 60. now that we are left with 60% of the cars, now the question states that 25% of the cars that contained one person were not wearing sunglasses. that just means that 25% of 60 = total amount of people wearing sunglasses. now to figure that out, I divided 60 by 4 because I know that 25 is exactly 1/4 of 100 which means I can just divide my number by 4 to get 25%. 60/4=15 which means 15% of the cars had one person that was not wearing sunglasses. Now all that needs to be done is to find the percent that is leftover, 100 - (40+15) = 45. so that means 45% of the cars had one person with sunglasses.
Grade 8 POTW I won't include too many unneeded words like anti-freeze until the end. First, as always, I'll list the facts. 3L bottle is 7%, 4L bottle is 20%, Bulk supply is 5%. All of the 3L and 4L is used. Goal: 8% I'll now do the math. 3L=3000mL 4L=4000mL 3000 divided by 100 = 30 x 7 = 210mL +4000 divided by 100 = 40 x 20 = +800mL 7000 =====================1010mL Glycerine Most of the calculations have just been done. Now, there could be a quicker method of doing this, but I'll do trial and error. Bulk Supply: Bulk supplies tend to be "a lot", so I'll begin with a value larger than 4L. XL = Xx1000mL After the = sign will now be the result of dividing by 20. 5000mL=250mL. I will also auto-add (skip showing the adding) to save time. 12000 divided by 100 = 120 x 8 = 960 doesn't equal 1260 10000mL=500mL 17000 divided by 100 = 170 x 8 = 1360 doesn't equal to 1510. 15000mL=750mL 22000 divided by 100 = 220 x 8 = 1760 equals 1760. Therefore, 22L of antifreeze from the bulk is needed. The 5% of glycerine will be 750mL.
Grade 8 POTW: This was kind of confusing to get my mind over, but here is how I did it: Let x be the number of liters I need to get 8% glycerine 3*0.07+4*0.2+0.05x = 0.08(3+4+x) 0.21 + 0.8 + 0.05x = 0.08x + 0.56 1.01 - 0.56 = 0.08x - 0.05x 0.03x = 0.45 x = 15 Therefore, you need 15 liters of the bulk anti-freeze to make the 8% glycerine anti-freeze. Here is what everything means: I let x be what I require, how many liters I should use to make what the customer wants. 3*0.07 is the amount of glycerine in the 3 liter bottle, since it has 7%. 4*0.2 is the amount of glycerin in the 4 liter bottle, since it has 20%. Finally, 0.05 x is the amount of glycerin in bulk. The right side is what you have with the 8% glycerin. So, they would be equal, and I figured out the algebra for the answer of 15 liters. -Alan
Bhavee's POTW#4 (Sign in issues solved) Since 40% percent of cars on a highway contained 2 or more people, it would be out of a hundred percent. So, 100%-40%=60%, it would mean that the other 60% of people are alone (excluding non-humans). 25% of 60% would be 15% (25% = 1/4)(1/4 of 60 would be 15) (I have absolutely no idea how to continue from here)
Grade 7 POTW (continued) okay I realised that the question states "NOT" and I somehow missed it. 15 would be the 25% not wearing sunglasses. 60 - 15 = 45. 45% of the people aren't wearing sunglasses.
40% = 2 or more people That means that there are 60% of cars that have one person in them. 25% of 60% are wearing sunglasses. The question is to find the percent of people WEARING sunglasses. 75% of 60% are wearing sunglasses. 60 / 4 = 25%, or 15 15 x 3 = 45. (45%) 45% of the cars have people wearing sunglasses.
So, I'm going to review the general information. 1. 40% of the cars have 2 or more people. This means that 60% of those cars have only one person in them. 2. Since 60% have one person in them, 25% of those people are NOT wearing sunglasses, but the question is to find the percentage of people that ARE wearing sunglasses. To do this, since this is out of 100 as it is percentage, and 60% is the people that have one person in them, and 25% the percentage that is not, I know that 25% is actually just 15% of the original 100% of cars, so I will subtract 15% from 60%, which leaves me with 45%. As a result, 45% percent of the cars with only one person in the them that are wearing sunglasses.
In order to solve this problem. I first found out the amount of glycerine in the mixture of the 3/4L bottles, by dividing the number of ml in each bottle by 100 and then multiplying the percentage of glycerine in the mixture. I found that there was 1010ml of glycerine in the 7000ml bottle, and that the mixture was made up of 14% glycerine.
The antifreeze has 50ml of glycerine per litre, so using that measurement and some trial and error, found that you will need 15L of the bulk antifreeze to make antifreeze with 8% glycerine
40% all cars have 2 or more people. 60% one person 25% NOT wearing sunglasses 45% of cars that have one person in it are wearing sunglasses. I found this by knowing that 25% is just 15% out of 60%. Therefore subtracting 15 from 60 leaves how many cars have one person and are wearing sunglasses.
Grade 7 POTW: Information: - 40% of cars = 2 or more people - 60% of cars = 1 person - Within that 60% of cars with 1 person, 75% are wearing sunglasses.
To find the percentage of cars that have one persona and are wearing sunglasses, you can mutiply 60 (percentage of cars with one person) by 0.75 (percentage of people wearing sunglasses in the 60% of cars with one person, in a decimal). Which is 45. Therefore, the percentage of cars with one persona and with sunglasses on is 45%
Grade 7 POTW #4: 40% of cars have two or more people. 100 - 40 = 60. 60% have one person. 25% of single person cars don't have sunglasses. 100 - 25 = 75 75% of single cars have sunglasses. 0.60 x 0.75 = 0.45 The percentage of cars with only one person in them that are wearing sunglasses is 45%.
60% of cars containing one person and 25% of those people were not wearing sunglasses. So 60*0.75 (0.75 being 75% which is the people who were wearing glasses) = 45%
If the sample size was 100 than 40% of 100 is 40. Than 100- 40 = 60, or, 60% of 100 = 60. If 25% of the 60% of 100 people aren’t wearing sunglasses is ¼ of 60. 60/4= 15. 15/100 is converted to 15%. 60- 15= 45%. From that math, the percentage of individual people with glasses on is 45%.
Grade 7 POTW 40% of cars = 2+ people assuming there are 100 people, 100% - 40% of cars with 2+ people = 60% of cars with singular drivers 25% of single ladies driving a vehicle aren't wearing their dope shutter shade sunglasses 100% of singular drivers - 25% glassesless = 75% who are wearing their shades
Here, the question is asking how many single drivers wearing glasses are there. 60% of 100% and 75% of 60%
The easiest way to calculate the final answer is multiply the two last sums. 60% x 75% = 0.45 0.45 into a percentage is 45% 45% of vehicles on the road are being driven by one person wearing sunglasses
2+ people=40% 1 person=60% 1 person without sunglasses=25% which equals 15% of total meaning if the total is 100% then there would be 2+ people (40%) + with one person (60%) of that 60% there is 15% not wearing glasses leaving 45% wearing glasses
Before the bulk supply is added, the mixture contains about 14% glycerin.Taking about 12 litres of bulk antifreeze would create as close of a mixture with litres as possible for it to be a whole number.
At first I did not understand the question, and had no idea on how to actually solve it. Looking at some of my peer's answers I somewhat grasped an understanding of how to actually get around this question. After mixing the 3 and 4 litre bottles of glycerin, I figured out that the bulk supply gave around 50mL of glycerin per litre. From there I simply multiplied the amount of glycerin until it was up to 8%. Therefore, the owner needs 15 litres of bulk supply, in order to create a solution that is 8% glycerin.
For the grade 8 potw I went to first figure out how much glycerin was in already. 3000ml+4000ml is 7000ml in total with 210ml+800ml of glycerin or 1010ml. Then for every liter of the bulk supply we add it adds 50ml of glycerin. Then from there I kept adding 50ml to the 1010ml of glycerin and 1000ml to the 7000ml until I got a match of 8% gylcerin with 15 extra liters of the bulk supply.
Grade 7 POTW: If 40% of all cars contained two or more people then that means 60% of all cars have only one person. 25% of the cars containing one person are not wearing sunglasses so that means 75% of the cars containing one person (60% of all cars on the road) are wearing sunglasses. To figure out how many people are in a car by themselves are wearing sunglasses I multiplied 0.75 x 0.60. I did this because I wanted to find 75% of the 60% of cars on the road. I got 45%. So 45% of all cars on the road with one person in it is wearing sunglasses.
POTW #4 40% of the people in the highway have two people in their vehicle, that means the other 60% only have one person in their vehicle. 25% of people in a 1 person car don't have sunglasses.
Since 60% of people are driving alone and 25% is a quarter of a whole (25% = 4 multiplied by a number equals the whole) 60/4 = 15 25% of people driving alone aren't wearing sunglasses 25% = 15 60 - 15 = 45 45% of people driving alone have sunglasses
Grade 8 POTW: After looking at some other people's answers I understood the question better, since at first I wasn't sure. After simplifying the information, it can be found that there's 50mL in each litre of the bulk supply. After some trial and error, 15L of the bulk supply brings the 14% of glycerine in the 3 and 4 litre anti-freeze supplies down to 8%.
Because 40% of people aren't driving on their own, it means that 60% of people are driving on their own. Within that 60% driving on their own, 25% are NOT wearing sunglasses, meaning that 25% are. These two percentages, 60% (percent of people driving on their own) and 75% (percent of people driving on their own WITH sunglasses), converted into decimals would be 0.60 and 0.75 respectively. 0.60 * 0.75 = 0.45
40% of people drive on their own and have sunglasses.
Grade 7 POTW:
ReplyDeleteThis question is pretty simple:
40% of cars have 2 or more people, so the percentage of cars that contain only one person is 60%. Out of these people, 25% of them do not wear sunglasses. This means that 15% of the original 100% of cars contain 1 person who does not wear sunglasses. This means that 60-15, which gives me 45%, of cars contain 1 person who wears sunglasses.
-Alan
Grade 7 POTW
ReplyDeleteIn order to find the answer to this POTW, I need to lay out the facts.
40% = 2 or more people, 25% of 1 person = sunglasses
So now we're onto the math. With 40% of the cars containing 2 or more people, the other 60% therefore has to contain 1 person since it's on a highway. It can't contain 0 people obviously due to many cars being in a highway and there is no parking. The only exceptions are when something like a car accident happened, but we're just going to assume its 1 person because the odds are small and if that is the case then "more info needed".
60% of the cars have 1 person. Now, using the next piece of data, we can find out how many people are wearing sunglasses with 1 person in the car. 25% of 1 person in the car is wearing sunglasses. So in other words, 25% of 60% of 100% is a 1-person-glasses-wearer in the car. 60% of 100 is 60%. 25% of 60% is 60 divided by (100 divided by 25 (4)) which is 15.
15% of all the cars in the highway contain 1 person only wearing sunglasses.
so first I can eliminate the option that doesn't contain one person which is that 40% of the cars had 2 or more people. so I subtracted that with the total percent, 100 - 40 which got me 60. now that we are left with 60% of the cars, now the question states that 25% of the cars that contained one person were not wearing sunglasses. that just means that 25% of 60 = total amount of people wearing sunglasses. now to figure that out, I divided 60 by 4 because I know that 25 is exactly 1/4 of 100 which means I can just divide my number by 4 to get 25%. 60/4=15 which means 15% of the cars had one person that was not wearing sunglasses. Now all that needs to be done is to find the percent that is leftover, 100 - (40+15) = 45. so that means 45% of the cars had one person with sunglasses.
ReplyDeletePlease still use COPS!
DeleteGrade 8 POTW
ReplyDeleteI won't include too many unneeded words like anti-freeze until the end.
First, as always, I'll list the facts.
3L bottle is 7%, 4L bottle is 20%, Bulk supply is 5%. All of the 3L and 4L is used.
Goal: 8%
I'll now do the math.
3L=3000mL 4L=4000mL
3000 divided by 100 = 30 x 7 = 210mL
+4000 divided by 100 = 40 x 20 = +800mL
7000 =====================1010mL Glycerine
Most of the calculations have just been done. Now, there could be a quicker method of doing this, but I'll do trial and error.
Bulk Supply:
Bulk supplies tend to be "a lot", so I'll begin with a value larger than 4L.
XL = Xx1000mL
After the = sign will now be the result of dividing by 20.
5000mL=250mL. I will also auto-add (skip showing the adding) to save time.
12000 divided by 100 = 120 x 8 = 960 doesn't equal 1260
10000mL=500mL
17000 divided by 100 = 170 x 8 = 1360 doesn't equal to 1510.
15000mL=750mL
22000 divided by 100 = 220 x 8 = 1760 equals 1760.
Therefore, 22L of antifreeze from the bulk is needed. The 5% of glycerine will be 750mL.
Sorry. Looked over and forgot to subtract the 7 L from the 3 and 4 L. So ya. 15 L is needed.
DeleteGrade 8 POTW:
ReplyDeleteThis was kind of confusing to get my mind over, but here is how I did it:
Let x be the number of liters I need to get 8% glycerine
3*0.07+4*0.2+0.05x = 0.08(3+4+x)
0.21 + 0.8 + 0.05x = 0.08x + 0.56
1.01 - 0.56 = 0.08x - 0.05x
0.03x = 0.45
x = 15
Therefore, you need 15 liters of the bulk anti-freeze to make the 8% glycerine anti-freeze.
Here is what everything means:
I let x be what I require, how many liters I should use to make what the customer wants.
3*0.07 is the amount of glycerine in the 3 liter bottle, since it has 7%.
4*0.2 is the amount of glycerin in the 4 liter bottle, since it has 20%.
Finally, 0.05 x is the amount of glycerin in bulk.
The right side is what you have with the 8% glycerin.
So, they would be equal, and I figured out the algebra for the answer of 15 liters.
-Alan
Bhavee's POTW#4 (Sign in issues solved)
ReplyDeleteSince 40% percent of cars on a highway contained 2 or more people, it would be out of a hundred percent. So, 100%-40%=60%, it would mean that the other 60% of people are alone (excluding non-humans). 25% of 60% would be 15% (25% = 1/4)(1/4 of 60 would be 15) (I have absolutely no idea how to continue from here)
Grade 7 POTW (continued)
ReplyDeleteokay I realised that the question states "NOT" and I somehow missed it. 15 would be the 25% not wearing sunglasses. 60 - 15 = 45. 45% of the people aren't wearing sunglasses.
40% = 2 or more people
ReplyDeleteThat means that there are 60% of cars that have one person in them.
25% of 60% are wearing sunglasses. The question is to find the percent of people WEARING sunglasses.
75% of 60% are wearing sunglasses.
60 / 4 = 25%, or 15
15 x 3 = 45. (45%)
45% of the cars have people wearing sunglasses.
So, I'm going to review the general information.
ReplyDelete1. 40% of the cars have 2 or more people. This means that 60% of those cars have only one person in them.
2. Since 60% have one person in them, 25% of those people are NOT wearing sunglasses, but the question is to find the percentage of people that ARE wearing sunglasses.
To do this, since this is out of 100 as it is percentage, and 60% is the people that have one person in them, and 25% the percentage that is not, I know that 25% is actually just 15% of the original 100% of cars, so I will subtract 15% from 60%, which leaves me with 45%.
As a result, 45% percent of the cars with only one person in the them that are wearing sunglasses.
Grade 8 POTW
ReplyDeleteIn order to solve this problem. I first found out the amount of glycerine in the mixture of the 3/4L bottles, by dividing the number of ml in each bottle by 100 and then multiplying the percentage of glycerine in the mixture. I found that there was 1010ml of glycerine in the 7000ml bottle, and that the mixture was made up of 14% glycerine.
The antifreeze has 50ml of glycerine per litre, so using that measurement and some trial and error, found that you will need 15L of the bulk antifreeze to make antifreeze with 8% glycerine
40% all cars have 2 or more people.
ReplyDelete60% one person
25% NOT wearing sunglasses
45% of cars that have one person in it are wearing sunglasses. I found this by knowing that 25% is just 15% out of 60%. Therefore subtracting 15 from 60 leaves how many cars have one person and are wearing sunglasses.
you don't need to say "test" every time.
ReplyDeleteGrade 7 POTW:
ReplyDeleteInformation:
- 40% of cars = 2 or more people
- 60% of cars = 1 person
- Within that 60% of cars with 1 person, 75% are wearing sunglasses.
To find the percentage of cars that have one persona and are wearing sunglasses, you can mutiply 60 (percentage of cars with one person) by 0.75 (percentage of people wearing sunglasses in the 60% of cars with one person, in a decimal). Which is 45. Therefore, the percentage of cars with one persona and with sunglasses on is 45%
VERY clear and concise Fiona!
DeleteGrade 7 POTW #4:
ReplyDelete40% of cars have two or more people. 100 - 40 = 60. 60% have one person.
25% of single person cars don't have sunglasses.
100 - 25 = 75
75% of single cars have sunglasses.
0.60 x 0.75 = 0.45
The percentage of cars with only one person in them that are wearing sunglasses is 45%.
Grade 7 POTW:
ReplyDelete100%-40%=60%
60% of cars containing one person and 25% of those people were not wearing sunglasses. So 60*0.75 (0.75 being 75% which is the people who were wearing glasses) = 45%
45% of cars with one person with sunglasses.
If the sample size was 100 than 40% of 100 is 40. Than 100- 40 = 60, or, 60% of 100 = 60. If 25% of the 60% of 100 people aren’t wearing sunglasses is ¼ of 60. 60/4= 15. 15/100 is converted to 15%. 60- 15= 45%. From that math, the percentage of individual people with glasses on is 45%.
ReplyDeleteGrade 7 POTW
ReplyDelete40% of cars = 2+ people
assuming there are 100 people,
100% - 40% of cars with 2+ people = 60% of cars with singular drivers
25% of single ladies driving a vehicle aren't wearing their dope shutter shade sunglasses
100% of singular drivers - 25% glassesless = 75% who are wearing their shades
Here, the question is asking how many single drivers wearing glasses are there.
60% of 100%
and 75% of 60%
The easiest way to calculate the final answer is multiply the two last sums.
60% x 75% = 0.45
0.45 into a percentage is 45%
45% of vehicles on the road are being driven by one person wearing sunglasses
2+ people=40%
ReplyDelete1 person=60%
1 person without sunglasses=25% which equals 15% of total meaning if the total is 100% then there would be 2+ people (40%) + with one person (60%) of that 60% there is 15% not wearing glasses leaving 45% wearing glasses
Before the bulk supply is added, the mixture contains about 14% glycerin.Taking about 12 litres of bulk antifreeze would create as close of a mixture with litres as possible for it to be a whole number.
ReplyDeleteGrade 8 POTW:
ReplyDeleteAmber and Cindy:
3000mL + 4000mL= 7000mL
210mL+800mL= 1010mL
-----
7000mL of anti-freeze and 1010mL of the glyerine. Now to find out how much bulk supply.
10000mL = 500mL
10000mL + 7000mL= 17000
500mL + 1010mL = 1510mL
1510 is not 8% of 17000 so it doesn't work. If you continue this, you'll eventually get to the answer which is:
15000mL of antifreeze = 750mL of glyerine
15000mL + 7000mL = 22000mL
750mL + 1010mL = 1760mL
22000mL * 0.08 = 1760mL
1760mL = 1760mL
Therefore, 15mL of the bulk supply is needed.
Grade 8 POTW fix:
ReplyDeleteIt's actually 15L, I made a mistake sorry.
At first I did not understand the question, and had no idea on how to actually solve it. Looking at some of my peer's answers I somewhat grasped an understanding of how to actually get around this question. After mixing the 3 and 4 litre bottles of glycerin, I figured out that the bulk supply gave around 50mL of glycerin per litre. From there I simply multiplied the amount of glycerin until it was up to 8%. Therefore, the owner needs 15 litres of bulk supply, in order to create a solution that is 8% glycerin.
ReplyDeleteFor the grade 8 potw I went to first figure out how much glycerin was in already. 3000ml+4000ml is 7000ml in total with 210ml+800ml of glycerin or 1010ml. Then for every liter of the bulk supply we add it adds 50ml of glycerin. Then from there I kept adding 50ml to the 1010ml of glycerin and 1000ml to the 7000ml until I got a match of 8% gylcerin with 15 extra liters of the bulk supply.
ReplyDeleteGrade 8 POTW:
ReplyDelete3L + 4L = 7L or 7000mL.
3L is 7% glycerin ----------------------> 3 * 0.07 = 0.21 L
4L is 20% glycerin ----------------------> 4 * 0.20 = 0.8 L
0.21 + 0.8 = 1.01 L or 1010 mL.
1010 / 7000 = 14%
I need 8%.
Bulk is usually very big so I'll start with 5L.
5000 * 0.05 = 250 mL of glycerin.
7000 + 5000 = 12000
1010 + 250 = 1260
1260 / 12000 = 11% <------- too much still
I need to assume that the the amount of glycerin is more. Lets try 7L.
7000 * 0.05 = 350mL of glycerin.
7000 + 7000 = 14000
1010 + 350 = 1360
1360 / 14000 = 10%
I still need to try a bit more. Only a bit though so I'll try 8L.
8000 * 0.05 = 400
7000 + 8000 = 15000
1010 + 400 = 1410
1410 / 15000 = 9%
I kept on going until I got...
15L of bulk
15000 * 0.05 = 750mL of glycerin.
7000 + 15000 = 22000
1010 + 750 = 1760
1760 / 22000 = 8% <----- Works
15 L of the bulk antifreeze is needed.
Grade 7 POTW:
ReplyDeleteIf 40% of all cars contained two or more people then that means 60% of all cars have only one person. 25% of the cars containing one person are not wearing sunglasses so that means 75% of the cars containing one person (60% of all cars on the road) are wearing sunglasses. To figure out how many people are in a car by themselves are wearing sunglasses I multiplied 0.75 x 0.60. I did this because I wanted to find 75% of the 60% of cars on the road. I got 45%. So 45% of all cars on the road with one person in it is wearing sunglasses.
POTW #4
ReplyDelete40% of the people in the highway have two people in their vehicle, that means the other 60% only have one person in their vehicle. 25% of people in a 1 person car don't have sunglasses.
Since 60% of people are driving alone and 25% is a quarter of a whole (25% = 4 multiplied by a number equals the whole)
60/4 = 15
25% of people driving alone aren't wearing sunglasses
25% = 15
60 - 15 = 45
45% of people driving alone have sunglasses
Grade 8 POTW:
ReplyDeleteAfter looking at some other people's answers I understood the question better, since at first I wasn't sure. After simplifying the information, it can be found that there's 50mL in each litre of the bulk supply. After some trial and error, 15L of the bulk supply brings the 14% of glycerine in the 3 and 4 litre anti-freeze supplies down to 8%.
Grade 8 POTW
ReplyDelete3L+4L=7L/7000mL
7% of 3L/3000mL is 0.21L (3 x 0.07 = 0.21L/210mL).
20% of 4L/4000mL is 0.8L (4 x 0.20 = 0.8L/800mL).
After adding 210mL and 800mL together, we get 1010mL.
We now need to find out how much bulk supply of antifreeze is needed.
I first tried to find out what percentage of the bottle was glycerin and I got 14% because I did:
1010/7000 which was 14%.
After a few attempts at guess and check, I ended up with 15L of the bulk supply that was required.
GRADE 7 POTW #4
ReplyDeleteBecause 40% of people aren't driving on their own, it means that 60% of people are driving on their own.
Within that 60% driving on their own, 25% are NOT wearing sunglasses, meaning that 25% are.
These two percentages, 60% (percent of people driving on their own) and 75% (percent of people driving on their own WITH sunglasses), converted into decimals would be 0.60 and 0.75 respectively.
0.60 * 0.75 = 0.45
40% of people drive on their own and have sunglasses.