Question 487851
A 37 year old father has a 4 year old son.
 In how many years will the father be exactly 4 times as old as his son.
:
Let y = no. of years until this is true
:
y + 37 = 4(y + 4)
y + 37 = 4y + 16
37 - 16 = 4y - y
21 = 3y
y = {{{21/3}}}
y = 7 years
:
:
You can confirm this: 37 + 7 = 4(7 + 4)