Two whales are moving in the same direction at 18 mps and 15 mps. The faster whale crosses the slow whale in 15 seconds. What is the length of the slower whale in meters?  Choices:
A) 45 m	B) 56 m	C) 39 m	D) 33 m	E) 62 m

Rationale: relative speed = ( 18 - 15 ) = 3 mps . distance covered in 15 sec = 15 * 3 = 45 m . the length of the faster train = 45 m . answer : a
Answer: A