1. A father is older than his son by 25years. 3years ago, the ratio of their ages was 3:1. Find their present ages

Let x represent the son's age

Let y represent to father's age

Two equations given

x + 25 = y

(y - 3) / 3 = (x - 3)

Sub 1st equation into the second and solve

((x+25) -3) / 3 = (x - 3)

x= 15.5 (son's age)

y= 40.5 (father's age)

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0