question_answer

'A can do a piece of work in 20 days and 'B' can do the same work in 15 days. How long will they take to finish the work, if both of them work together?

A) \[13\frac{1}{2}\]days      

B) 10 days

C) \[13\frac{4}{7}\]days     

D) \[17\frac{1}{2}\]days