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 and b together can do a piece of work in 6 days and a alone can do it in 13 days . in how many days can b alone can do it ? 
Options: a ) 12 days , b ) 15 days , c ) 78 / 7 days , d ) 21 days , e ) 22 / 7 days
[EX A]: c

[EX Q]: Problem: a car travels at a speed of 12 miles per hour . how far will it travel in 5 hours ? 
Options: a ) 50 miles , b ) 60 miles , c ) 72 miles , d ) 22 miles , e ) 62 miles
[EX A]: b

[EX Q]: Problem: two trains 120 meters and 165 meters in length respectively are running in opposite directions , one at the rate of 80 km and the other at the rate of 65 kmph . in what time will they be completely clear of each other from the moment they meet ? 
Options: a ) 7.16 , b ) 7.16 , c ) 7.07 , d ) 7.15 , e ) 7.11
[EX A]:
c