Explain 15 th question

​Q15. 8 men and 12 boys can finish a piece of work in 10 days while 6 men and 8 boys can finish the same in 14 days. Find the time taken by 1 man alone to finish the work and that taken by one boy alone to finish the work.
    

 Let the part of the job done by 1 men per day be x

Let the part of the job done by 1 boy per day be y

So,

Multiply equation 1 by 3 and equation 2 by 4 to get,

add and subtract equation 3 and 4, to get

So the time taken by the boy to complete the job alone will be 280 days and for the men will be 140.