A and B working separately can do a piece of work in 9 and 12 days respectively. If they work for a day alternately. If A begins first, in how many days the work will be completed ?

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Two pipes can fill a tank in 10 hrs. and 12 hrs. respectively while a third pipe empties the full tank in 20 hrs.  If all the three pipes operate together , in how much time the tank will be filled ? 

A. 7.5 hrs B. 5 hrs C. 7 hrs D. None of these...

If 6 men working together can complete 50 identical tasks in 4 hours then how many such identical tasks can be completed if 10 men are working together for 6 hours?

A. 20 B. 25 C. 125 D. 60...

Running at the same constant rate, 6 identical machines can produce a total of 270 bottles per minute. At this rate, how many bottles could 10 such machines produce in 4 minutes?

A. 2700 B. 1080 C. 450 D. 1800...

P and Q need 8 days to complete a work. Q and R need 12 days to complete the same work. But P, Q and R together can finish it in 6 days. How many days will be needed if P and R together do it?

A. 7 B. 8 C. 9 D. 10...

Two taps X and Y can fill a tank in 10 hrs. and 15 hrs.respectively.  If the both taps are opened together, the tank will be full in_________?

A. 3 hrs. B. 4 hrs, C. 5 hrs. D. 6 hrs....