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: 8 persons can build a wall 140 m long in 42 days . in how many days can 30 persons complete a similar wall 100 m long ? 
Options: a ) 12 , b ) 10 , c ) 8 , d ) 6 , e ) 5
[A]: c


[Q]: Problem: a man can do a piece of work in 4 days , but with the help of his son he can do it in 3 days . in what time can the son do it alone ? 
Options: a ) 12 days , b ) 6 days , c ) 5 days , d ) 4 days , e ) none of these
[A]: a


[Q]: Problem: the angle between the minute hand and the hour hand of a clock when the time is 10.30 , is 
Options: a ) 35 ° , b ) 65 ° , c ) 45 ° , d ) 135 ° , e ) 95 °
[A]:
d