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
