Q11. 
A cylindrical overhead tank is filled by two pumps $P_1$ and $P_2$. $P_1$ can fill the tank in 8 hr while $P_2$ can fill the tank in 12 hr. There is a pipe $P_3$ which can empty the tank in 8 hr. Both the pumps are opened simultaneously. The supervisor of the tank, before going out on a work, sets a timer to open $P_3$ when the tank is half filled so that the tank is exactly filled up by the time he is back. Due to technical fault $P_3$ opens when the tank is onethird filled. If the supervisor comes back as per the plan what percent of the tank is till empty? 
A.  $15\%$ 

B.  $12\%$ 

C.  $10\%$ 

D.  None of these 
Q12. 
A and B working together can finish a job in T days. If A works alone and completes the job, he will take T+5 days. If B works alone and completes the same job, he will take T+45 days. What is T? 
A.  25 Days 

B.  60 Days 

C.  15 Days 

D.  None of these 
Q13. 
Three professors Dr. Gupta, Dr. Sharma, Dr. Singh are evaluating answer script of a subject. Dr. Gupta is $40%$ more efficient than Dr. Sharma, who is $20%$ more efficient than Dr. Singh. Dr. Gupta takes 10 days less than Dr. Sharma to complete the evaluation work. Dr. Gupta starts the evaluation work and works for 10 days and then Dr. Sharma takes over. Dr. Sharma evaluates for next 15 days and then stops. In how many days, Dr. Singh can complete the remaining evaluation work? 
A.  7.2 days 

B.  9.5 days 

C.  11.5 days 

D.  None of these 
Q14. 
$X$ alone can do a piece of work in 15 days and $Y$ alone can do it in 10 days. $X$ and $Y$ undertook to do it for Rs. 720. With the help of $Z$ they finished it in 5 days. How much is paid to $Z$? 
A.  Rs. 360 

B.  Rs. 120 

C.  Rs. 240 

D.  Rs. 300 
Q15. 
A work is done by 30 workers not all of them have the same capacity to work. Every day exactly 2 workers, do the work with no pair of workers working together twice. Even after all possible pairs have worked once, all the workers together works for two more days to finish the work. Find the number of days in which all the workers together will finish the whole work? 
A.  31 

B.  29 

C.  41 

D.  48 