Q11. 
There are 12 pipes attached to a tank. Some of them are fill pipes and some are drain pipes. Each of the fill pipes can fill the tank in 12 hours, while each of the drain pipes will take 24 hours to drain a full tank completely. If all the pipes are kept open when the tank was empty, it takes 2 hours for the tank to overflow. How many of these pipes are drain pipes? 
A.  6 

B.  11 

C.  4 

D.  7 
Q12. 
A bath can be filled by the cold water pipe in 10 min and by hot water pipe in 15 min (independently each). A person leaves the bathroom after turning on both pipes simultaneously and returns at the moments when the bath should be full. Finding, however, that the waste pipe has been open he now closes it. In 4 min more, bath is full. In what time would be the waste pipe empty it? 
A.  9 min 

B.  12 min 

C.  15 min 

D.  14 min 
Q13. 
The digging work of the DMRC on the AdohiniAndheriamore stretch requires Twentyfour men to complete the work in sixteen days. As a part of the task if DMRC were to hire Thirtytwo women, they can complete the same work in twentyfour days. Sixteen men and sixteen women started working and worked for twelve days. Due to time bound schedule the work had to be completed in remaining 2 days, for which how many more men are to be employed? 
A.  48 

B.  24 

C.  36 

D.  16 
Q14. 
When Abhinav and Bipul are working alone, they can complete a piece of work in 25 days and 30 days respectively. On day 1, Bipul started the work and Abhinav joined B from day 3 onwards. Find after how many days will the work be completed? 
A.  13 

B.  11 

C.  15 

D.  16 
Q15. 
In Nuts And Bolts factory, one machine produces only nuts at the rate of 100 nuts per minute and needs to be cleaned for 5 minutes after production of every 1000 nuts. Another machine produces only bolts at the rate of 75 bolts per minute and needs to cleaned for10 minutes after production of every 1500 bolts. If both the machines start production at the same time, what is the minimum duration required for producing 9000 pairs of nuts and bolts? 
A.  130 minutes 

B.  135 minutes 

C.  170 minutes 

D.  180 minutes 