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Q:

# The ratio of efficiencies of two filling pipes is 4 : 5. There is a third emptying pipe which efficiency is two third of the average efficiency of first two filling pipes can empty a filled tank in 36 minutes. In how much time both the filling pipes can fill the tank when it is empty?

 A) 16 min B) 12 min C) 14 min D) 20 min

Answer:   B) 12 min

Explanation:

Let the efficiencies of filling pipes is 4p and 5p respectively.

Efficiency of pipe which empty the tank = 2/3 x 9p/2 = 3p

Total work = 3p x 36 = 108p

Time to fill the tank by both the pipes = 108p/9p = 12 min.

Q:

One fill pipe A is 3 times faster than second fill pipe B and takes 32 minutes less than the fill pipe B. When will the cistern be full if both pipes are opened together?

 A) 6 min B) 8 min C) 12 min D) 10 min

Answer & Explanation Answer: C) 12 min

Explanation:

Let pipe A takes p min to fill

Then,

pipe B takes 3p min to fill

=> 3p - p = 32

=> p = 16 min => 3p = 48 min

Required, both pipes to fill = (48 x 16)/(48 + 16) min = 12 min.

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8 835
Q:

In what time would a cistern be filled by three pipes which diameters are 2 cm, 3 cm and 4 cm running together, when the largest alone can fill it is 58 minutes? The amount of water flowing in each pipe is proportional to the square of its diameter.

 A) 26 min B) 32 min C) 36 min D) 42 min

Answer & Explanation Answer: B) 32 min

Explanation:

Given that the diameters of the three pipes are 2 cm, 3 cm and 4 cm

From the given data,

Amount of water from three pipes is 4 units, 9 units and 16 units.

Let the capacity of cistern be 'p' units.

∴ p/58 = 16

⇒ p = 928 units.

In 1 minute, quantity to be filled by 3 pipes = 29 units

∴ Total time required = 928/29 = 32 minutes.

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2 1669
Q:

Two filling taps P and Q together can fill a tank with rate of 40 lit/min and 60 lit/min respectively in 8 min. If a waste tap can empty the filled tank in 32 min, then what is the rate of waste tap ?

 A) 34 lit/min B) 25 lit/min C) 22 lit/min D) 18 lit/min

Answer & Explanation Answer: B) 25 lit/min

Explanation:

Given that the waste tap can empty the filled tank in 32 min.

Now, the rate at which the waste tap can empty the tank = (40 + 60)8/32 = 100/4 = 25 lit/min.

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7 721
Q:

The capacity of a tank is 2400 $m3$.  A pump can be used both for filling and emptying the tank.  The emptying capacity of the pump is 10 $m3$/minute higher than its filling capacity. And also, the pump needs 8 minutes less to empty the tank than to fill it. Find the filling capacity of the pump.

 A) 46 cub.m/min B) 44 cub.m/min C) 48 cub.m/min D) 50 cub.m/min

Answer & Explanation Answer: D) 50 cub.m/min

Explanation:

Let filling capacity of the pump be 'F' $m3/min$

Then, the filling capacity of the pump will be (F + 10) $m3/min$

From the given data,

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12 1840
Q:

A water tank in a village is normally filled in 8 hours but takes 2 hours longer to fill because of a leak in its bottom. If the tank is full, in how many hrs will the leak empty it ?

 A) 34 hrs B) 36 hrs C) 38 hrs D) 40 hrs

Answer & Explanation Answer: D) 40 hrs

Explanation:

The time taken by the leak to empty the tank =

Therefore, the leak empties the tank in 40 hours.

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9 2457
Q:

Two pipes A and B can fill a tank in 16 hrs and 12 hrs respectively. The capacity of the tank is 240 liters. Both the pipes are opened simultaneously and closed after 2 hrs. How much more water need to fill the tank?

 A) 70 lit B) 170 lit C) 90 lit D) 190 lit

Answer & Explanation Answer: B) 170 lit

Explanation:

Given A alone can fill the tank of capacity 240 lit in 16 hrs.

=> A can fill in 1 hr = 240/16 = 15 lit

=> B alone can fill the tank of capacity 240 lit in 12 hrs.

=> B can fill in 1 hr = 240/12 = 20 lit

Now, (A + B) in 1 hr = 15 + 20 = 35 lit

But they are opened for 2 hrs

=> 2 x 35 = 70 lit rae filled

Remaining water to be filled in tank of 240 lit = 240 - 70 = 170 lit.

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16 2877
Q:

A and B can fill the tank in 60 min and 90 min. There is a leak at 3/4th of the height. If leak is opened alone, it takes 36 min to empty till 3/4th the height. Find the time taken to fill the tank if all of the taps and the leak are opened simultaneously.

 A) 39 B) 27 C) 37 D) 33

Answer & Explanation Answer: A) 39

Explanation:
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34 4424
Q:

Water flows into a tank which is 200 m long and 150 m wide, through a pipe of cross-section (0.3m x 0.2m) at 20 km/h. In what time will the water level be 12m  ?

 A) 200 hrs B) 240 hrs C) 300 hrs D) 270 hrs

Answer & Explanation Answer: C) 300 hrs

Explanation:

Volume of water collected in the tank in 1 hour

⇒ (0.3 × 0.2 × 20km × 1000mts) = 1200 m cubic

If after t hours, the water is at height of 12m,

1200t=200×150×12

⇒ t = 300 Hours.

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15 5929