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 10 days . b alone can finish it in 20 days . in how many days can a alone finish the work ? 
Options: a ) 20 , b ) 10 , c ) 15 , d ) 5 , e ) 7
[EX A]: a

[EX Q]: Problem: a and b together can do a work in 4 days . if a alone can do it in 20 days . in how many days can b alone do it ? 
Options: a ) 11 , b ) 5 , c ) 6 , d ) 8 , e ) 25
[EX A]: b

[EX Q]: Problem: the circumference of the front wheel of a cart is 30 ft long and that of the back wheel is 32 ft long . what is the distance traveled by the cart , when the front wheel has done five more revolutions than the rear wheel ? 
Options: a ) 20 ft , b ) 25 ft , c ) 750 ft , d ) 900 ft , e ) 2400 ft
[EX A]:
e