Uday working 4 hours a day completes a work in 10 days, while Subhash working 8 hours a day can complete the same work in 15 days. How many days will it take for both of them working together 10 hours a day to complete the work ?

Explanation

It is clear from the question that
Uday completes the work in `(4xx10)` hours = 40 hours and Subhash completes the same work in `(8xx15)` = 120 hours
`therefore` Work done in 1 hour, when both working together will be Hence, both working together will complete the work in 30 hours.
`because` Both working together 10 hours a day
`rArr` Both working together 30 hours in `1/(10) xx30` = 3 days
`therefore` Required time = 3 days.