The total ages of A, B and C at present is 150 years. Ten years ago the ratio of their ages was 3 : 2 : 1 . Find the present age of B.

47 60 50 55

50

According to question,      A  :   B   :   C      3  :    2   :   1         ( 10 years ago )  Now,  let age of C = X , age of B = 2x and age of A = 3x  x + 10 + 2x + 10 + 3x + 10 = 150 6x = 120  x = 20  present age of B = 2 × 20 + 10 = 50 years