Question

the sum of the present ages of a father and his son is 60 years. five years ago, father's age was four times the age of son.so now the son's age will be​

Answer 1

Let father's age be 'f' and sons age be 's'

Present ages:

f + s = 60 ------ (1)

Five years ago,

Father's age = f - 5

Sons age = s - 5

According to question,

(f - 5) = 4(s - 5)

⇒ f - 5 = 4s - 20

⇒f - 5 + 20 = 4s

⇒ f + 15 = 4s

⇒ f - 4s = -15 ----- (2)

(1) - (2)

f + s = 60

(-) f - 4s = -15

5s = 75

⇒s = 15

Substitute value of s in equation 1,

f + s = 60

f + 15 = 60

⇒ f = 45

∴ Present age of son = 15 years