 Hello and welcome to the session. In this session we discussed the following question which says A and B working together can finish a piece of work in 5 days. By A alone can do it in 10 days. How much time will be alone take to finish it? Let's move on to the solution. Now time taken by A and B together to finish the work is equal to 5 days. Then time taken by A alone to finish the work is equal to 10 days. In 5 days A and B together finish a piece of work. So A plus B's 1 day work is given by 1 upon 5. This means in 1 day A and B together finish 1 upon 5 of the work. Now in 10 days A finishes the work alone. So A's 1 day work is given by 1 upon 10. So from here we can easily find out B's 1 day work and this is equal to A plus B's 1 day work minus A's 1 day work and so this is equal to 1 upon 5 minus 1 upon 10 which comes out to be equal to 1 upon 10. So we get B's 1 day work would be 1 upon 10. That is B finishes 1 tenth of the work in 1 day. So this would mean time taken by B alone to finish the work would be equal to 10 days. Since in 1 day the work finished by B would be 1 tenth of the work. So in 10 days B finishes the whole work. So final answer is 10 days. This completes the session. Hope you have understood the solutions for this question.