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'.

[Q]: Problem: 45 men working 8 hours per day dig 40 m deep . how many extra men should be put to dig to a depth of 50 m working 6 hours per day ? 
Options: a ) 10 , b ) 20 , c ) 30 , d ) 40 , e ) 50
[A]: c


[Q]: Problem: two trains 120 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 which they take to cross each other is ? 
Options: a ) 10.9 , b ) 10.7 , c ) 10.3 , d ) 10.08 , e ) 10.2
[A]: d


[Q]: Problem: if the weight of 12 meters long rod is 13.4 kg . what is the weight of 6 meters long rod ? 
Options: a ) 6.7 kg . , b ) 10.8 kg . , c ) 12.4 kg . , d ) 18.0 kg , e ) none
[A]:
a