Question

roberts father is 4 times as old as robert. after 5 years his father will be three time as old as robert. find their present ages

Answer 1

Let Robert’s age be x years.

Then Robert’s father’s age = 4x

After 5 years, Robert’s age = x + 5

Father’s age = 4x + 5

According to the question,

4x + 5 = 3(x + 5)

⇒ 4x + 5 = 3x + 15

⇒ 4x - 3x = 15 - 5

⇒ x = 10

⇒ 4x = 4 × 10 = 40

Answer 2

Step-by-step explanation:

Let Robert's age be x

Robert's father age = 4x

After 5 yrs,

Robert's age =x+5

Robert's father age = 4x+ 5

According to the question, we get 3(x+5)= 4x+5

3x+15=4x+5

3x-4x=5-15

x=10

Robert's age= x=10

Robert's father age= 4x+5=4×10+5=45