Friday, September 19, 2014

Another Year, Another POTW (Math Problem of the Week #1)



Welcome back all returning Cranny Intermediates, and hello to all you new Intermediates! (i.e. Grade 7s). As most of you know, this blog is a space where your teachers can share various things with you. We often reflect about field trips, post videos, share articles, but MOST OFTEN, we challenge you with the Math Problem of the Week Questions! (A.K.A. POTW).

Another great function of this blog is that it contains our wonderful Intermediate calendar (look to the right). Please use this to track dates and deadlines, and also to keep your parents in-the-loop about your schooling.

The most important requirement of this blog is YOUR participation. That may be your sharing of a POTW answer, your comments to others, or even just that you are reading and following new posts. With that being said, it is absolutely pivotal that you remind yourself about online netiquette. You must always consider the feelings of others when posting comments. Before you press 'submit' or 'send' or 'publish' please ask yourself two questions: "Would I say this to someone's face?" and "Is my comment helpful in any way?" If the answer to either of those questions is "No" then consider revising your comment.

Without further ado, below is your first POTW for the year! Please submit any and all responses regardless if you think someone else has the same answer. You can always show your work in different ways! And be sure to comment on other students' work, provide feedback, and ask clarifying questions.












16 comments:

  1. Since it shows unknown since I haven't setup my google profile for blogger (on school account) as of now - I am Anish A.

    I feel that the answer is his score already (75%) + (9%) which would mean his new average would be 84%.

    How did I get this?

    Since his new math score is 93...I subtracted 93-39 and received 54. 54 is the missing percentage. To find the new percentage i divided 54 by the 6 subjects and received an added percentage of 9 (%) ... therefore meaning his new average is 84%.

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  2. Stu Dent's real average was 84. First, we multiply 75 by 6 because that will give us all his test scores added up. 75 x 6 = 450. Then, we subtract 39 from 450 to get what his other 5 scores are. 450 - 39 = 411. Now we add 93 to 411 to replace 39 and see what his real test scores add up to. 411 + 93 = 504. Now to find the real average we must divide it by the number of subjects. 504 / 6 = 84. Stu's report card was DENTed.

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  3. (93-39=54)/6=9+75=84

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    Replies
    1. Please explain and give full sentence responses.

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    2. mr milette, did mine send I wasn't sure if it worked

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    3. It didn't send Aparna. Remember you have to sign in as I showed you in class.

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  4. 75%x6=450% so 450% is the total percentage of the 6 subjects. 450%-39%=411%. 411%+93% (Actual percentage)=504%. 504% divided by 6 is 84%. Therefore, the real average is 84%.

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  5. Stu Dent's actual average is 84%. I know this because since I want to add back the percentage that was miscalculated, I subtracted 39 from 93 and got 54 to get the missing percent. Then I divided 54 by the amount of tests he took which was 6 to get the percent that I should add to the current one. I got 9 so 9+75=84. So his percentage would be 84%.

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  6. To find the correct average, you must find out the sum of the marks all added together, then subtract the incorrect mark and replace it with the correct one, then divide it by the amount of marks (6) to find the correct average. In other words: (75x6-39+93)/6=the correct report card average. So 75x6=450, the sum of all the marks added together, then 459-39=441, 441+93=534, the correct sum of all the marks added together. 534/6 is the average. So 84% is the correct average

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    Replies
    1. I like seeing this question solved in a variety of ways. Great work.

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  7. Stu Dent's real average should be 84%.
    I know this because, first I multiplied 75 by 6 to get his total score added up which is 450. Then, I subtracted 93 by 39 and added the difference to 450 as his score should have been higher. The sum was 504 so I divided it by 6 to get his real average which is 84%. Therefore, his real average is 84%)

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  8. To find the answer, we can work backwards. First, I multiply 6x75 to find Stu's total scores on his report card. this gives me 450. I know that he already got the 39 percent, so he only needs 54 more. So I add 54+450=504. The process of finding the mean is adding all the data together and then dividing the sum by the amount of data points in the set (each number). I have already found the sum of the data, and now I have to divide by the amount of individual data pieces in the set, AKA each number. That would be 6. 504/6 is 84. So Stu Dent's real average for his report card would be 84%

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    Replies
    1. You're right Serena, working backwards is an effective problem solving strategy for this question. Are there any other strategies you used? Any others you might use?

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  9. love the turn out of this question! You are all quite proficient at finding the correct answer, and many of you share similar strategies and show solid understanding of the Math behind finding the average. I am interested in hearing from you all what you think about Anish's approach. Does it make sense? Why?

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  10. 75x6=450, 450-39=411, 411+93= 504, 504÷6=84
    Stu Dent's correct average is 84%. I know because his fake average is 75, and the formula for average is to add all the numbers in a data set together and then dividing them by the frequency of the numbers, so by doing the opposite and multiplying 75 by 6, we get 450, since 39 in incorrect, we do 450-39, which gives 411, since 93 is the correct score, we add that so we get 504, 504 is the correct total of all the scores, so by following the formula for mean, and dividing it by 6, we get 84. Therefore, Stu Dent's correct average is 84%

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  11. 75x6=450
    450-39=411
    411 + realscore 93=504
    504/6 (mean) to get 84% as the real score

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