Adam tried to compute the average of his 7 test scores, he mistakenly divided the correct sum of his test scores by 6, which yielded 84. What is Adams correct average test score??? I know how to find the mean, I just dont know how to do it this way!!!
2007-04-12 07:19:34 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Assume that all the scores were the same. (Then the mean would be the same as that score.)
7x / 6 = 84
7x = 504
x = 72
2007-04-12 07:24:25 · answer #1 · answered by Mathematica 7 · 0⤊ 2⤋
Simple! Average of a total N divided by 6 = 84 so the total must be 84 X 6 = 504 and that divided by 7 gives the correct average of 504/7 = 72
You can get the same result by simply multiplying that average by 6/7
84 X 6/7 = 72
2007-04-12 07:26:10 · answer #2 · answered by Swamy 7 · 0⤊ 0⤋
If Adam divided the sum of his test scores by 6 and got 84, then the correct sum is 6*84, or 504. When we divide this by 7 we get an average of 72.
2007-04-12 07:25:07 · answer #3 · answered by Cody P 2 · 0⤊ 0⤋
The mean is the sum of the scores divided by the total number of scores.
You are told that there were 7 test scores but that Adam divided by 6. You are also told that the "incorrect" mean is 84.
84 = sum of scores / 6
6 * 84 = sum of scores
Thus, you can retrieve the original sum of the scores by multiplying 84 by 6. You do not need to know the original individual scores pre-summation.
Finally, to obtain the correct mean, divided the sum of the scores by 7. (ie, 84 * 6 / 7 )
2007-04-12 07:24:34 · answer #4 · answered by Skep 2 · 0⤊ 0⤋
Since Adam divided by 6, you need to multiply the 84 by 6.
That will give you the sum of the test scores. Then divide by the correct number, 7.
2007-04-12 07:22:44 · answer #5 · answered by morningfoxnorth 6 · 1⤊ 0⤋
First, multiply 6 by 84 to get the original total (504). Now divide 504 by 7 to get 72.
2007-04-12 07:23:30 · answer #6 · answered by BB 2 · 0⤊ 0⤋
The total of his tests was 6*84.
Take this total and divide it by 7.
2007-04-12 07:23:22 · answer #7 · answered by Anonymous · 0⤊ 0⤋
mean =sum /number of scores
84 is the sum he made a mistake 84= sum/6
so the sum is 84*6= 504
if he divises by 7 he finds 504/7 =72
2007-04-12 07:26:01 · answer #8 · answered by maussy 7 · 0⤊ 0⤋
Multipy the mistaken number,84 by 6 = 504
Since this is the sum of 7 numbers, to find the mean, divide this by 7
So 504/7 = 72
2007-04-12 07:21:44 · answer #9 · answered by Anonymous · 2⤊ 0⤋
Well, the average is the number you get when you divide the sum of all results by n, the number of samples.
So, adam divided by 6. He did this:
sum/6
When he should have done this:
sum/7
So all you'd have to do is undo his mistake, and then calculate it the right way.
2007-04-12 07:23:04 · answer #10 · answered by Brian L 7 · 0⤊ 0⤋
(sum)/6 = 84
(6/7)*(sum)/6 = (6/7)*84
sum/7 = 72
2007-04-12 07:26:02 · answer #11 · answered by fcas80 7 · 0⤊ 0⤋