How many paying stones, each measuring 2 1/2 m * 2 m are required to pave a rectangular court yard 50 m long and 16 1/2 m board?  Pick
A) 99 B) 18 C) 165 D) 10 E) 15

Rationale: 50 * 33 / 2 = 5 / 2 * 2 * x = > x = 165 answer : c
Answer: C