Let the present age of father be x years. Then,
Son’s present age = (45 – x) years
Five years ago,
Age of Father = (x – 5) years
and Age of Son = (45 – x – 5) years = (40 – x) years
According to given condition,
(x – 5) (40 – x) = 124
⇒ 40x – x2 – 200 + 5x = 124
⇒ x2 – 45x + 324 = 0
⇒ x2 – 36x – 9x + 324 = 0
⇒ x (x – 36) – 9 (x – 36) – 0
⇒ (x - 9) (x - 36) = 0
⇒x = 9 or x = 36
When x = 36, we have
Father’s present age = 36 years
Son’s present age = 9 years
When x = 9, we have
Father’s present age = 9 years
Son’s present age = 36 years
Clearly, this is not possible
Hence, Father’s present age = 36 years and Son’s present age = 9 years.