Question

A father is 3 times as old as his son and his daughter is 3 years younger than the son. Fi the sum of there ages 3 years ago was 63 find the present age of the father.

Answer 1

Answer:the present age of the father is 45 years

Step-by-step explanation:

Let x represent the present age of the father.

Let y represent the present age of the son.

Let z represent the age of the daughter.

A father is 3 times as old as his son. This means that

x = 3y

his daughter is 3 years younger than the son. It means that

z = y - 3

The sum of their ages 3 years ago was 63. This means that

x - 3 + y - 3 + z - 3 = 63

x + y + z - 9 = 63 - - - - - - - - - - 1

Substituting x = 3y and z = y - 3 into equation 1, it becomes

3y + y + y - 3 - 9 = 63

5y - 12 = 63

5y = 63 + 12 = 75

y = 75/5 = 15

x = 3y = 3 × 15

x = 45

z = y - 3 = 15 - 3

z = 12