A completes a work in 12 days and B complete the same work in 20 days. If both of them work together, then the number of days required to complete the work will be  Options:
A) 8 days B) 9 days C) 7.5 days D) 12 days E) 13 days
If A can complete a work in x days and B can complete the same work in y days, then, both   of them together can complete the work in x y/ x+ y days   Therefore, here, the required number of days = 12 × 20/ 32 = 7.5 days.   7.5 days
<result>C</result>
A completes a work in 12 days and B complete the same work in 20 days. If both of them work together, then the number of days required to complete the work will be