30 pens and 75 pencils were purchased for 510. If the average price of a pencil was 2.00, find the average price of a pen.\nOptions:\n(A) 10\n(B) 11\n(C) 12\n(D) cannot be determined\n(E) None of the above
Let’s work this out in a step by step way to be sure we have the right answer.
(C)
Since average price of a pencil = 2\n∴ Price of 75 pencils = 150\n∴ Price of 30 pens = (510 – 150) = 360\n∴ Average price of a pen = 360⁄60 = 12.

The answer is (C)