Answer :
Let us say that:
K = age of Kristen
B = age of Ben
From the problem, we make the equations:
eqtn 1: K + B = 32
eqtn 2: (K – 4) = 2 (B – 4)
Simplifying eqtn 2:
K – 4 = 2 B – 8
K = 2 B – 4
Plugging in this to eqtn 2:
(2 B – 4) + B = 32
3 B – 4 = 32
3 B = 36
B = 12
From eqtn 2:
K = 2 B – 4 = 2 (12) – 4 = 20
So Kristen is 20 while Ben is 12.