Question

11. The present age of a father is thrice that of
his daughter. 15 years ago, the age of the father
was 6 times that of his son. If the daughter is
4 years younger than the son, determine the present
age of the father.
CAS
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Answer 1

Answer:-

Let the present age of the daughter be "x" years.

Given:-

The present age of the father is thrice her daughter's age.

→ Father's age = 3x

15 years ago, age of the father was six times the son and the daughter is 4 years younger than the son.

→ Daughter's age(x) = Son's age - 4

→ Son's age = (x + 4 ) years.

Father's age before 15 years = (3x - 15)

Son's age before 15 years = x + 4 - 15 = x - 11

→ 3x - 15 = 6(x - 11)

→ 3x - 15 = 6x - 66

→ 3x - 6x = - 66 + 15

→ - 3x = - 51

→ 3x = 51

Hence, the Present age of father is 51 years.

→ Daughter's age (x) = 51/3 = 17 years.

→ Son's age (x + 4) = 17 + 4 = 21 years.