P is able to do a piece of work in 10 days and Q can do the same work in 12 days. If they can work together for 5 days, what is the fraction of work left?	Choose the correct choice from the following.
A) 7 / 12
B) 5 / 12
C) 1 / 12
D) 3 / 12
E) 1 / 2

Rationale: "explanation : amount of work p can do in 1 day = 1 / 10 amount of work q can do in 1 day = 1 / 12 amount of work p and q can do in 1 day = 1 / 10 + 1 / 12 = 11 / 60 amount of work p and q can together do in 5 days = 5 × ( 11 / 60 ) = 11 / 12 fraction of work left = 1 – 11 / 12 = 1 / 12 answer : option c"
Answer: C