An alloy is to contain copper and zinc in the ratio 9:4. The zinc required to be melted with 24kg of copper is? Select
A) 12 kg
B) 8.3 kg
C) 10.7 kg
D) 15.5 kg
E) 7 kg

Rationale: "let the required quantity of copper be x kg 9 : 4 : : 24 : x 9 x = 4 * 24 x = 10 2 / 3 kg = 32 / 3 = 10.7 kg answer is c"
Answer: C