Question

An electrician and his assistant take up electrical work in Mr.Sharma's house.The electrician can complete the job in 10 days,while his assistant can complete the same job in 15 days.They start working together,but 2 days later,the electrician leaves the job and goes away.How long will it take for the assistant to complete the remaining job?

Answer 1

This question is about time and work.

Electrician can complete 1/10 of total work in one day and

Assistant 1/15 of total work in one day.

When they work together per day work done = $\frac{1}{10} +\frac{1}{15} = \frac{1}{6}$

First two days work completed = 2(1/6) = 1/3

Remaining work to be done= 1-(1/3) = 2/3

Now assistant alone works.

1/15 of work can be completed by asst. alone in 1 day

2/3 or work can be completed by asst. in $\frac{\frac{2}{3} }{\frac{1}{5} } =\frac{10}{3}$

Answer is 10/3 days.