A and B together can complete a work in 12 days. A alone complete it in 20 days. If B does the work only for half a day daily, then in how many days A and B together will complete the work?
Pick one: A) 110 days B) 11 days C) 15 days D) 20 days E) 17 days
B's one day work= (1/12 - 1/20) = 1/30.   Now, (A+B)'s one day work = (1/20+1/60) = 1/15. [∵ B work for half day only].   So, A and B together will complete the work in 15 days.   15 daysORRE15 daysT ANSWER: "15 days".
<result>C</result>
A and B together can complete a work in 12 days. A alone complete it in 20 days. If B does the work only for half a day daily, then in how many days A and B together will complete the work?