Aptitude :: Time and Work

1.	Twenty women can do a work in sixteen days. Sixteen men can complete the same work in fifteen days. What is the ratio between the capacity of a man and a woman?
	A. 3 : 4 B. 4 : 3 C. 5 : 3 D. Data inadequate

2.

X and Y can do a piece of work in 20 days and 12 days respectively. X started the work alone and then after 4 days Y joined him till the completion of the work. How long did the work last?

A. 6 days B. 10 days C. 15 days D. 20 days answer the above questions. in comment's