Question

After installing a new pool, Kedrick's family is going to use two pumps to fill it. Pump 1 can fill a pool in 8 hours while pump 2 can fill it in 12 hours.

a. Determine how fast the pool can be filled using both pumps.
b. If both pumps start at the same time, but pump 1 breaks down after an hour, find how long it will take to fill the pool (in total).

SHOW THE WAY.​

Answer 1

Answer:

ANSWER

Work efficiency of pump A in emptying pool =

4

1

per hour

Work efficiency of pump B in emptying pool =

6

1

per hour

∴ work done by A and B together =

4

1

+

6

1

=

24

10

per hour

Hence time taken to fill the tank 100% =

10

24

hours

∴ time taken to fill 50% =

5×100

12×50

= 1.2 hours

Since, 1hour=60minutes

∴1.2 hours= 1.2×60=72 minutes

72 minutes = (60+12) minutes = 1hour 12minutes

So, the answer is option A

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