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: circular gears p and q start rotating at the same time at constant speeds . gear p makes 10 revolutions per minute and gear q makes 40 revolutions per minute . how many seconds after the gears start rotating will gear q have made exactly 5 more revolutions than gear p ? 
Options: a ) 6 , b ) 8 , c ) 10 , d ) 12 , e ) 15
[EX A]: c

[EX Q]: Problem: two trains 140 m and 160 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks . the time ( in seconds ) which they take to cross each other , is : 
Options: a ) 9 , b ) 9.6 , c ) 10 , d ) 10.8 , e ) 7
[EX A]: d

[EX Q]: Problem: a can do a work in 15 days and b in 20 days . if they work on it together for 4 days , then the fraction of the work that is left is : 
Options: a ) 1 / 4 , b ) 1 / 10 , c ) 7 / 15 , d ) 8 / 15 , e ) 9 / 15
[EX A]:
d