Question 677779
x=one number
4x=the other number

x+4x=sum of the two numbers
(x+4x)/2= half the sum of the two numbers
Soooo
(x+4x)/2=10 multiply both sides by 2
5x=20
x=4----one number
4x=4*4=16 the other number 
CK
16+4=20
20/2=10
10=10

Hope this helps---ptaylor