Time and Work Practice Test 2 with solutions

Question : 27 of 40

Marks: +1, -0

Two pipes can fill a tank in 8 hours and 12 hours respectively whereas an escape pipe can empty it in 6 hours. If the three pipes are opened at 1 p.m., 2 p.m. and 3 p.m. respectively, at what time will the tank be filled?

7.00 a.m.
8.00 a.m.
5.00 a.m.
7.30 a.m.

Validate

Solution:

Let tank will be filled up after t hours of starting of pipe A;
Then, t ×

1/8

+ (t - 1) ×

1/{12}

- (t - 2) ×

1/6

= 1
⇒

t(1/8 + 1/{12}-1/6) - 1/{12}+1/3

= 1
⇒

t× 1/{24}

1 - 1/4

∴ t =

3/4 × 24

= 18 hours
Hence, required time = 1 p.m. + 18 hours = 7 a.m.

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