Question

Mr. lal cam do a job in 15 days , and his son can do it in 10 days. how long would it take them to do the job (in days) if they worked together

Answer 1

let A do work in 1 day=1/15
B do work in 1 day=1/10
work together =1/15+1/10
4+6/60
10/60=1/6
here they take 6 days