P is 30% more efficient than Q. P can complete a work in 23 days. If P and Q work together, how much time will it take to complete the same work?	Choose the correct answer.
A) 9  B) 10  C) 11  D) 13  E) 15

Rationale: "work done by p in 1 day = 1 / 23 let work done by q in 1 day = q q × ( 130 / 100 ) = 1 / 23 = > q = 100 / ( 23 × 130 ) = 10 / ( 23 × 13 ) work done by p and q in 1 day = 1 / 23 + 10 / ( 23 × 13 ) = 23 / ( 23 × 13 ) = 1 / 13 = > p and q together can do the work in 13 days option d"
Answer: D