**Q.10** P, Q, R and S are working on a project. Q can finish the task in 25 days, working alone for 12 hours a day. R can finish the task in 50 days, working alone for 12 hours per day. Q worked 12 hours a day but took sick

leave in the beginning for two days. R worked 18 hours a day on all days. What is the ratio of work done by Q and R after 7 days from the start of the project.

**(A)** 10 : 11

**(B)** 11 : 10

**(C)** 20 : 21

**(D)** 21 : 20

**Answer: (C)**

**Explanation:**