In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: the speed at which a man can row a boat in still water is 15 km / hr . if he rows downstream , where the speed of current is 3 km / hr , how many seconds will he take to cover 90 meters ? 
Options: a ) 12 , b ) 16 , c ) 17 , d ) 18 , e ) 20
d

Problem: a can do a piece of work in 4 hours ; b and c together can do it in 2 hours , while a and c together can do it in 2 hours . how long will b alone take to do it ? 
Options: a ) 12 , b ) 9 , c ) 8 , d ) 6 , e ) 4
e

Problem: a train is 360 meter long is running at a speed of 45 km / hour . in what time will it pass a bridge of 160 meter length ? 
Options: a ) 11 seconds , b ) 41.6 seconds , c ) 40 seconds , d ) 88 seconds , e ) 19 seconds

b