Exercise :: Time and Work  General Questions
21.  A takes twice as much time as B or thrice as much time as C to finish a piece of work. Working together, they can finish the work in 2 days. B can do the work alone in: 

Answer: Option B Explanation:
x = 12. So, B takes (12/2) = 6 days to finish the work. 
22.  A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in : 

Answer: Option C Explanation:
Hence, the total time taken = (10 + 2) = 12 days. 
23.  A and B can do a piece of work in 30 days, while B and C can do the same work in 24 days and C and A in 20 days. They all work together for 10 days when B and C leave. How many days more will A take to finish the work? 

Answer: Option A Explanation:

24.  A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work in : 

Answer: Option A Explanation: Ratio of rates of working of A and B = 2 : 1. So, ratio of times taken = 1 : 2.
So, A and B together can finish the work in 4 days. 
25.  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? 

Answer: Option B Explanation: (20 x 16) women can complete the work in 1 day.
(16 x 15) men can complete the work in 1 day.
