A contractor engaged 15 men to complete a job in 12 days. However, he soon found that 3 small boys can do the work of one man and have to be paid less. If he engaged 6 boys and 7 men to complete a job, find the time taken by them to complete the job.
Since he hired 6 boys thats equivalent to 2 men
So totally he hired 9 men to complete the job
15 men do 100% work in 12 days.
Product of man-days = 15*12
9 men do 100% work in x days.
Product = 9x
9x = 15*12