P can do a work in the same time in which Q and R together can do it. If P and Q work together, the work can be completed in 10 days. R alone needs 20 days to complete the same work. then Q alone can do it in Choose the correct choice from the following answers
A) 20	B) 22	C) 25	D) 27	E) 40
Work done by P and Q in 1 day = 1/10   Work done by R in 1 day = 1/20   Work done by P, Q and R in 1 day = 1/10 + 1/20 = 3/20   But Work done by P in 1 day = Work done by Q and R in 1 day . Hence the above equation can be written as Work done by P in 1 day Ã— 2 = 3/20   =&gt; Work done by P in 1 day = 3/40   =&gt; Work done by Q and R in 1 day = 3/40   Hence work done by Q in 1 day = 3/40 â€“ 1/20 = 1/40   So Q alone can do the work in 40 days   Answer is 40.
<result>E</result>
P can do a work in the same time in which Q and R together can do it. If P and Q work together, the work can be completed in 10 days. R alone needs 20 days to complete the same work. then Q alone can do it in