SOLUTION: Average we have: 10 , 10 , and 1 we found their average and it was 7. we found it by (10+10+1)/3 so we got the total average but what if the total average is given , and

Algebra ->  Average -> SOLUTION: Average we have: 10 , 10 , and 1 we found their average and it was 7. we found it by (10+10+1)/3 so we got the total average but what if the total average is given , and       Log On


   



Question 761933: Average

we have: 10 , 10 , and 1 we found their average and it was 7. we found it by
(10+10+1)/3
so we got the total average
but what if the total average is given , and 2 numbers are give how will we find the firt lets see :
10 , 10 , x total makes 7
Find X

Found 2 solutions by Cromlix, Alan3354:
Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
You have three numbers and their average is 7
7 * 3 = 21 Total before averaging
10 + 10 + x = 21
20 + x = 21
x = 21 -20
x = 1
Hope this helps.
:-)

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
10 , 10 , x total makes 7
-------------
Sum = # of elements * average
There are 3 elements, so 10 + 10 + x = 3*7 = 21
x = 1