Two pipes A and B can fill a tank in 36 hours and 45 hours respectively. If both the pipes are opened simultaneously, how much time will be taken to fill the tank?

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 :

• [A] 4 days
• [B] 6 days
• [C] 8 days
• [D] 18 days

If one pipe A can fill a tank in 20 minutes, then 5 pipes, each of 20% efficiency of A, can fill the tank in:

• [A] 80 min
• [B] 100 min
• [C] 20 min
• [D] 25 min

If 10 cats can kill 10 rats in 10 minutes how long will it take 100 cats to kill 100 rats?

• [A] 1 minutes
• [B] 10 minute
• [C] 100 minutes
• [D] 10000 minutes
• [E] None of these

A and B can do a job together in 7 days. A is 1 ³/₄ times as efficient as B. The same job can be done by A alone in :

• [A] 9 ¹/₃ days
• [B] 11 days
• [C] 12 ¹/₄ days
• [D] 16 ¹/₃ days

A pipe can fill a tank in 0.9 hours and another pipe can empty in 0.7 hours. If tank is completely filled and both pipes are opened simultaneously then 450 liters of water is removed from the tank is 2.5 hours. What is the capacity of the tank?

• [A] 200 liters
• [B] 350 liters
• [C] 456 liters
• [D] 567 liters
• [E] None of these