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 start walking from a place at a uniform speed of 7 kmph in a particular direction . after half an hour , b starts from the same place and walks in the same direction as a at a uniform speed and overtakes a after 1 hour 48 minutes . find the speed of b . 
Options: a ) 4.7 kmph , b ) 7.6 kmph , c ) 4 kmph , d ) 7 kmph , e ) 5.3 kmph
[A]: b


[Q]: Problem: if 42 men do a work in 25 days , in how many days will 50 men do it ? 
Options: a ) 23 , b ) 22 , c ) 19 , d ) 20 , e ) 21
[A]: e


[Q]: Problem: working alone at its constant rate , machine a produces x boxes in 10 minutes and working alone at its constant rate , machine b produces 3 x boxes in 5 minutes . how many minutes does it take machines a and b , working simultaneously at their respective constant rates , to produce 3 x boxes ? 
Options: a ) 3 minutes , b ) 4 minutes , c ) 4.2 minutes , d ) 6 minutes , e ) 12 minutes
[A]:
c