Two trains, one from Howrah to Patna and the other from Patna to Howrah, start simultaneously. After they meet, the trains reach their destinations after 4 hours and 16 hours respectively. The ratio of their speeds is?	Choose the correct answer
A) 4 : 5  B) 4 : 2  C) 4 : 4  D) 4 : 8  E) 4 : 1

Rationale: "let us name the trains a and b . then , ( a ' s speed ) : ( b ' s speed ) = √ b : √ a = √ 16 : √ 4 = 4 : 2 answer : b"
Answer: B