18
Q:

# Three taps A,B and C can fill a tank in 12,15 and 20 hours respectively. If A is open all the time and B ,C are open for one hour each alternatively, the tank will be full in:

 A) 6 hrs B) 20/3 hrs C) 7 hrs D) 15/2 hrs

Answer:   C) 7 hrs

Explanation:

Now, it is  the turn of A and B (3/20) part is filled by A and B in 1 hour.

Therefore, Total  time taken to fill the tank =(6+1)hrs= 7 hrs

Q:

The capacity of a tank is 2400 ${\mathbf{m}}^{\mathbf{3}}$.  A pump can be used both for filling and emptying the tank.  The emptying capacity of the pump is 10 ${\mathbf{m}}^{\mathbf{3}}$/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' ${\mathbf{m}}^{\mathbf{3}}\mathbf{/}\mathbf{min}$

Then, the filling capacity of the pump will be (F + 10) ${\mathbf{m}}^{\mathbf{3}}\mathbf{/}\mathbf{min}$

From the given data,

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8 445
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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8 825
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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11 780
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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18 1297
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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8 1657
Q:

A Tank is normally filled in 9 hours but takes four hours longer to fill because of a leak in its bottom. If the tank is full, the leak will empty it in ?

 A) 32.5 hrs B) 29.25 hrs C) 30.30 hrs D) 31 hrs

Answer & Explanation Answer: B) 29.25 hrs

Explanation:

Let the leak will empty the tank in x hrs

Then, 1/9 - 1/x = 1/13

x = 29.25 hrs

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5 1446
Q:

A tap can fill a tank in 6 hours. After half the tank is filled three more similar taps are opened. What is the total time taken to fill the tank completely ?

 A) 4 hrs 15 min B) 3 hrs 24 min C) 4 hrs 51 min D) 3 hrs 45 min

Answer & Explanation Answer: D) 3 hrs 45 min

Explanation:

Time taken by one tap to fill half of the tank = 3 hrs.

Part filled by the taps in 1 hour = 4 x 1/6 = 2/3

Remaining part = 1 - 1/2 = 1/2

2/3 : 1/2 :: 1 : p

p = 1/2 x 1 x 3/2 = 3/4 hrs. i.e., 45 min

So, total time taken = 3 hrs 45 min.

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7 2234
Q:

A large tanker can be filled by two pipes A and B in 60 and 40 minutes respectively. How many minutes will it take to fill the tanker from empty state if B is used for half the time and A and B fill it together for the other half ?

 A) 31 min B) 29 min C) 28 min D) 30 min

Answer & Explanation Answer: D) 30 min

Explanation:

Part filled by (A + B) in 1 minute = (1/60 + 1/40) = 1/24
Suppose the tank is filled in x minutes.
Then, x/2(1/24 + 1/40) = 1
(x/2) * (1/15) = 1 => x = 30 min.

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5 2581