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 49 hours and 64 hours respectively. The ratio of their speeds is  Choose the correct choice from the following answers.
A) 2 : 3  B) 5 : 9  C) 6 : 7  D) 8 : 11  E) None
Sol.   Let us name the trains as A and B. Then,   (A's speed) : (B's speed) = √b : √a   = √64 : √49   = 8 : 7.   Answer None
<result>E</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 49 hours and 64 hours respectively. The ratio of their speeds is