Krishna can do a work in 10 days while Mohan can do the same work in 20 days. They started work together. After 3 days Krishna left the work and Mohan completed it. For how many days Mohan worked alone more than the No. of days required when both worked together?

Krishna's efficiency = 10%
Mohan's efficiency = 5%
Work done by Krishana and mohan together in 3 days = 15 x 3 = 45%
Now, number of days in which B completed rest (55%) work alone = 55/5 = 11
Total No. of days in which B worked = 3 + 11 = 14
Now No. of days required by B, when A and B both worked together = 100/15 = 6²/₃
∴ Required difference in No. of days = (11) - (6²/₃)
= 13/3 = 4 1/3 days