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 64 hours and 121 hours respectively. The ratio of their speeds is
Choose the correct choice from the following:  A) 8 : 7  B) 11 : 8  C) 6 : 7  D) 9 : 16  E) None
Sol.   Let us name the trains as A and B. Then,   (A's speed) : (B's speed) = √b : √a   = √121 : √64   = 11 : 8.   Answer 11 : 8
<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 64 hours and 121 hours respectively. The ratio of their speeds is