SOLUTION: the average of 9 numbers is 45. if 90 and 88 are added to the set of numbers, what will be the resulting average

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Question 1092018: the average of 9 numbers is 45. if 90 and 88 are added to the set of numbers, what will be the resulting average
Found 3 solutions by ankor@dixie-net.com, greenestamps, ikleyn:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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the average of 9 numbers is 45.
if 90 and 88 are added to the set of numbers, what will be the resulting average
:
Now you are averaging 11 numers
A = %28%2845%289%29%2B90%2B88%29%29%2F11
A = %28%28405%2B178%29%29%2F11
A = 583%2F11
A = 53 is the new average

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!

We can also solve this kind of problem using a less formal mathematical method.

The average of the current 9 numbers is 45. The two added numbers are 90 and 88; the first is 45 above the current average and the second is 43 above the current average.

So when the two new numbers are added, making a total of 11 numbers in all, the total of all the numbers, compared to the current average of 45, has 88 "extra" points. We can divide that number of extra points by the new number of tests to see on average how many "extra" points each test has. 88 divided by 11 is 8. So, compared to the previous average, each test has an average of 8 more points.

So the new average is 8 points above the previous average: 45+8 = 53.

Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
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