Question

Robert's father is 4 times as old as robert. After 5 years, father will be three times as old as robert.What is their present ages of robert and his father respectively

Answer 1

Answer: Robert's present age is 10 years

Robert father's present age is 40 years

Step-by-step explanation:

Let r = Robert's current age

Let y = Robert father's current age

Robert's father is 4 times as old as robert. This means that

y = 4x

After 5 years, Robert's father will be three times as old as Robert. This means that

y + 5 = 3(x+5)

y + 5 = 3x + 15 - - - - - - - ;1

We will substitute y = 4x into equation 1. It becomes

4x + 5 = 3x + 15

Collecting like terms,

4x - 3x = 15 - 5

x = 10

y = 4x

Substituting x = 10,

y = 4× 10 = 40 years