A is twice as fast as B. If B alone can do a piece of work in 30 days, in what time can A and B together complete the work?  Choose the most appropriate option
A) 10  B) 99  C) 72  D) 26  E) 81
A can do the work in 30/2 i.e., 15 days.   A and B's one day's work = 1/15 + 1/30 = (2 + 1)/30 = 1/10   So A and B together can do the work in 10 days.   10nswer: 10
<result>A</result>
A is twice as fast as B. If B alone can do a piece of work in 30 days, in what time can A and B together complete the work?