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: 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
[A]: a


[Q]: Problem: a trader sells 45 meters of cloth for rs . 4500 at the profit of rs . 12 per metre of cloth . what is the cost price of one metre of cloth ? 
Options: a ) rs . 80 , b ) rs . 85 , c ) rs . 88 , d ) rs . 100 , e ) none of these
[A]: c


[Q]: Problem: a train running at the speed of 58 km / hr crosses a pole in 9 seconds . find the length of the train ? 
Options: a ) 145 , b ) 272 , c ) 278 , d ) 277 , e ) 112
[A]:
a