Task: Question Answering
Input (English): Problem: 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 16 hours and 4 hours respectively . the ratio of their speeds is : 
Options: a ) 2 : 4 , b ) 4 : 3 , c ) 6 : 7 , d ) 9 : 16 , e ) none of these
Output (English): a