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: 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: hcf and lcm two numbers are 20 and 396 respectively . if one of the numbers is 36 , then the other number is ? 
Options: a ) 36 , b ) 66 , c ) 132 , d ) 264 , e ) 220
[EX A]: e

[EX Q]: Problem: tom , working alone , can paint a room in 6 hours . peter and john , working independently , can paint the same room in 3 hours and 5 hours , respectively . tom starts painting the room and works on his own for one hour . he is then joined by peter and they work together for an hour . finally , john joins them and the three of them work together to finish the room , each one working at his respective rate . what fraction of the whole job was done by peter ? 
Options: a ) 19 / 35 , b ) 23 / 42 , c ) 27 / 55 , d ) 31 / 63 , e ) 35 / 74
[EX A]:
d