A hall 36m long and 15m broad is to be paved with stones, each measuring 5dm by 5 dm. The number of stones required is:
Choices:
A) 180	B) 1800	C) 18	D) 2160	E) 1.8

Rationale: "area of the hall = 3600 * 1500 area of each stone = ( 50 * 50 ) therefore , number of stones = ( 3600 * 1500 / 50 * 50 ) = 2160 answer : d"
Answer: D