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 can do a piece of work 60 days . b can do work in 20 days . in how many days they will complete the work together ?
Options: a ) 12 days , b ) 16 days , c ) 15 days , d ) 17 days , e ) 18 days
[A]: c

[Q]: Problem: mary can do a piece of work in 28 days . rosy is 40 % more efficient than mary . the number of days taken by rosy to do the same piece of work is ?
Options: a ) 22 , b ) 24 , c ) 20 , d ) 25 , e ) 27
[A]: c

[Q]: Problem: 75 men working 8 hours per day dig 50 m deep . how many extra men should be put to dig to a depth of 70 m working 6 hours per day ?
Options: a ) 75 , b ) 45 , c ) 55 , d ) 65 , e ) 35
[A]:
d