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 one
A) 4:5
B) 4:2
C) 4:4
D) 4:8
E) 4:1
Let us name the trains A and B.   Then, (A's speed) : (4:2's speed)   = √b : √a = √16 : √4   = 4:2   Answer: 4:2
<result>B</result>
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?