How many paying stones, each measuring 3 * 2 m are required to pave a rectangular court yard 15 m long and 6 m board?
Choices: A) 99 B) 18 C) 26 D) 15 E) 12

Rationale: "15 * 6 = 3 * 2 * x = > x = 15 answer : d"
Answer: D