Q21. 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. 10 days
B. 20 days
C. 15 days
D. 6Â days
Q22. X can do a piece of work in 40 days. He works at it for 8 days arid then Y finished it in 16 days. How long will they together take to complete the work ?
A. 20 days
B. 56 days
C. 15 days
D. 40/3 days
Q23. A and B can do a piece of work in 45 days and 40 days respectively. They began to do the work together but A leaves after some days and then B completed the remaining work in 23 days. The number of days after which A left the work was :
A. 9
B. 8
C. 6
D. 12
Q24. A does   of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work ?
A. 40 days
B. 37 days
C. 75/2 days
D. 23 days
Q25. 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 :
A. 1/10
B. 1/4
C. 8/15
D. 7/15
Q26. A man can do a job in 15 days. His father takes 20 days and his son finishes it in 25 days. How long will they take to complete the job if they all work together ?
A. Exactly 6 days
B. Less than 6 days
C. Approximately 6.4 days
D. More than 10 days
Q27. A machine P can print one lakh books in 8 hours, machine Q can print the same number of books in 10 hours while machine R can print them in 12 hours. All the machines are started at 9 a.m. while machine P is closed at 11 a.m. and the remaining two machines complete the work. Approximately at what time will the work be finished ?
A. 1 p.m.
B. 11:30 a.m.
C. 12 noon
D. 12:30 p.m.
Q28. 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 ?
A. 24 days
B. 18 days
C. 36 days
D. 30 days
Q29. A is thrice as good a workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in :
A. 20 days
B. 45/2 days
C. 30 days
D. 25 days
Q30. A can finish a work in 18 days and B can do the same work in 15 days. B worked for 10 days and left the job. In how many days, A alone can finish the remaining work ?
A. 5
B. 8
C. 6
D. 11/2
