In one alloy there is 12% chromium while in another alloy it is 8%. 20 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy. Find the percentage of chromium in the new alloy. Choose the correct choice from the following choices.
A) 9.45 % B) 10 % C) 15 % D) 20 % E) 25 %

Rationale: "the amount of chromium in the new 20 + 35 = 55 kg alloy is 0.12 * 20 + 0.08 * 35 = 5.2 kg , so the percentage is 5.2 / 55 * 100 = 9.2 % . answer : a ."
Answer: A