<PRE><B>Question 208630</B>
A man who is 40 years old has three sons, ages 6,3,and 1 . 
in how many years will the combined age of his three sons equal 80% of his age?
:
Let x = no. of years for this to be true
:
(x+6) + (x+3) + (x+1) = .8(x+40)
:
3x + 10 = .8x + 32
:
3x - .8x = 32 - 10
:
2.2x = 22
x = {{{22/2.2}}}
x = 10 years
:
:
See if that is true
16 + 13 + 11 = .8(50)
40 = 40</PRE>