Let's define:
x: Colette's age
y: Jack's age
If Colette is 4 times as old as Jack, then:
x = 4y
Given that Colette is 52, then x = 52, which means that
52 = 4y
4 is multiplying on the right, then it will divide on the left
52/4 = y
13 = y
Jack's age is 13
