Welcome to Adda
Hi Suman,
We normally do it using LCM concept. A question would have helped. So let me explain it by using an example.
Ram working can finish a job 10 days and Shyam workinga lone can do the job in 15 days. If they work on alternate days with Ram starting the work, how many days will it take to complete the work.
So let the work to be done be 30 units. So Ram does 3 units of work daily while Shyam does 2 units of work daily.
Ram starts the work so on 1st day 3 units of work will be done, on second day 2 units of work will be done and this will go on . So in every two days 5 units of work will be completed. Thus it will take 30/5 = 6 such pairs to complete the work. Each pair consists of 2 days so total days would be 12.
Hope that helps. You can also refer to my answer here, https://cracku.in/adda/banking/a-can-do-a-piece-of-work-in-10-days-while-b-can-d/2299
which is based on a similar concept.
Thanks.
