SOLUTION: If the average ( arithmetic mean ) of a and –5 is 10, then a = 25 15 5 -5 -15

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Question 1116490: If the average ( arithmetic mean ) of a and –5 is 10, then a =
25
15
5
-5
-15
Found 2 solutions by math_helper, greenestamps:
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
To average the two numbers, you add them and divide by 2:
(a + (-5))/2 = 10
(a - 5)/2 = 10
Solve this equation for a and you have the answer.

Answer by greenestamps(13216) About Me  (Show Source):
You can put this solution on YOUR website!


The average of two numbers is halfway between the two numbers.

The given number, -5, is 15 less than the given average, 10; the other number has to be 15 more than the average.

The other number is 10+15 = 25.