SOLUTION: the average of nine numbers is 72 and the average of four of them is 40. what is the average of the other 5? How do I show the workings for this question?

Algebra ->  Average -> SOLUTION: the average of nine numbers is 72 and the average of four of them is 40. what is the average of the other 5? How do I show the workings for this question?      Log On


   

Question 353604: the average of nine numbers is 72 and the average of four of them is 40. what is the average of the other 5?
How do I show the workings for this question?
Found 2 solutions by Fombitz, ewatrrr:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
%28A%2BB%2BC%2BD%2BE%2BF%2BG%2BH%2BI%29%2F9=72
.
.
A%2BB%2BC%2BD%2BE%2BF%2BG%2BH%2BI=648
.
.
%28A%2BB%2BC%2BD%29%2F4=40
.
.
A%2BB%2BC%2BD=160
.
.
highlight%28A%2BB%2BC%2BD%29%2BE%2BF%2BG%2BH%2BI=648
highlight%28160%29%2BE%2BF%2BG%2BH%2BI=648
E%2BF%2BG%2BH%2BI=488
Now find the average for these 5 numbers.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
Hi
Let a, b, c, and d represent the four numbers with an average of 40
(a+b+c+d)/2 =40
(a+b+c+d) =80
.
let u,v,w,y and z represent the remaining of the nine numbers
.
questions states
[(a+b+c+d) + (u+v+w+y+z)]/ 2 = 72
.
[(a+b+c+d) + (u+v+w+y+z)]= 144
80 + (u+v+w+y+z) = 144
(u+v+w+y+z) = 64
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(u+v+w+y+z)/2 = 32 (the average of the remaining five numbers)
.
check your answer
(80 + 64)/2 = 72