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'.

[EX Q]: Problem: a man rows his boat 75 km downstream and 45 km upstream , taking 2 1 / 2 hours each time . find the speed of the stream ? 
Options: a ) 6 , b ) 7 , c ) 5 , d ) 8 , e ) 9
[EX A]: a

[EX Q]: Problem: two cyclist start on a circular track from a given point but in opposite direction with speeds of 7 m / s and 8 m / s . if the circumference of the circle is 630 meters , after what time will they meet at the starting point ? 
Options: a ) 20 sec , b ) 15 sec , c ) 42 sec , d ) 50 sec , e ) 1 min
[EX A]: c

[EX Q]: Problem: a pipe can fill a cistern in 66 minutes . find the time in which 1 / 11 part of the cistern will be filled ? 
Options: a ) 5 min , b ) 2 min , c ) 6 min , d ) 1 min , e ) 10 min
[EX A]:
c