(A) 21:5
(B) 29:5
(C) 27:4
(D) 21:3
Correct Option is: A
At age of son be x and as father’s age is 9 times the age of her son, let it be 9x, nine years ago.
At present: father’s age will be (9x + 30) and son’s age will be (x + 30)
After 30 years: father’s age will be (9x + 30) +30 and son’s age will be (x + 30) + 30
father’s age is thrice that of son
(9x + 30) +30 = 3 [(x + 30) + 30]
(9x + 60) = 3[x + 60]
Solving the equation, we get x = 20
We are asked to find the present ratio.
(9x + 30) : (x + 30) = 210 : 50 = 21:5