P is four times as fast as Q and working together, they can complete a work in 5 days. In how many days can Q alone complete the work?  Select the correct option:
A) 5 3/4 days B) 6 1/4 days C) 16 days D) 25 days E) 18 days
P = 4Q   P + Q = 4Q + Q = 5Q   These 5Q people can do the work in 5 days, which means Q can do the work in 25 days.   Hence, P can do the work in 6 1/4 days.   ANSWER:6 1/4 days
<result>B</result>
P is four times as fast as Q and working together, they can complete a work in 5 days. In how many days can Q alone complete the work?