Time and Work problems - Aptitude Questions and Answers

Time and Work problems :

1 . A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With help of C, they did the job in 4 days only. Then, C alone can do the job in: 48/5 34/5 67/5 56/5 2. A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is : 8/15 9/15 9/45 8/45 3. A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day? 15 days 56 days 13 days 10 days 4. A is thrice as good as workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in: 45/2 4/5 2/3 1/2 5. A alone can do a piece of work in 6 days and B alone in 8 days. A and B undertook to do it for Rs. 3200. With the help of C, they completed the work in 3 days. How much is to be paid to C? Rs. 400 Rs. 800 Rs. 789 Rs. 700 6 . 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? 10 days 8 days  6 days  19 days 7. A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days? 13 days 6 days 26 days 8 days   8. Ravi and Kumar are working on an assignment. Ravi takes 6 hours to type 32 pages on a computer, while Kumar takes 5 hours to type 40 pages. How much time will they take, working together on two different computers to type an assignment of 110 pages? 8 hours 15 min 7 hours 45 min 6 hours 45 min 9 hours 45 min   9. Sakshi can do a piece of work in 20 days. Tanya is 25% more efficient than Sakshi. The number of days taken by Tanya to do the same piece of work is: 13 16 15 20 10.  A, B and C can complete a piece of work in 24, 6 and 12 days respectively. Working together, they will complete the same work in: 24/7 5 6 5/8