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 of a boat in still water in 42 km / hr and the rate of current is 6 km / hr . the distance travelled downstream in 44 minutes is : 
Options: a ) 86.6 km , b ) 46.6 km , c ) 35.2 km , d ) 35.6 km , e ) 26.6 km
c

Problem: a train running at the speed of 120 km / hr crosses a pole in 18 seconds . what is the length of the train ? 
Options: a ) 560 , b ) 570 , c ) 580 , d ) 590 , e ) 600
e

Problem: a can do a piece of work in 21 days and b in 28 days . together they started the work and b left after 4 days . in how many days can a alone do the remaining work ? 
Options: a ) 22 , b ) 88 , c ) 27 , d ) 14 , e ) 99

d