Question 204706
Let m = man's present age
Let s = son's present age
:
Write an equation for each statement:
:
"ten years ago a man was 3 times as old as his son."
m - 10 = 3(s-10)
m - 10 = 3s - 30
m = 3s - 30 + 10
m = 3s - 20; use for substitution below
:
" in 6 years, he will be twice as old as his son."
m + 6 = 2(s+6)
m + 6 = 2s + 12
m = 2s + 12 - 6
m = 2s + 6
:
 how old are they now?
Replace m with (3s - 20) in the above equation
3s - 20 = 2s + 6
3s - 2s = 6 + 20
s = 26 yrs is son's present age
then
m = 2s + 6
m = 2(26) + 6
m = 58 yrs is man's present age
:
:
Check solution in the statement:
"ten years ago a man was 3 times as old as his son. "
58 - 10 = 3(26 - 10)
48 = 3(16)