Given: A’s age = 4/5 of B’s age B’s age = 6/4 of C’s age Calculation: Let age of A, B and C be x, y and z respectively x = 4/5 of y ⇒ x/y = 4/5 ⇒ x : y = 4 : 5 ----(1) y = 6/4 of z ⇒ y/z = 6/4 = 3/2 ⇒ y : z = 3 : 2 ----(2) Multiply by 3 in equation (1) and multiply by 5 in equation (2), we get x : y : z = 12 : 15 : 10 According to question, 10 units = 60 years ⇒ 1 unit = 6 years ⇒ 12 units = 72 years ∴ Age of A is 72 years