Question

A cold water pipe can fill a swimming pool in 4 hours, and a hot water pipe in 6 hours. If cold water pipe is turned on and hot water pipe is turned on 3 hours later then how long will it take them to fill the pool together?

Answer 1

Answer:

0.6 hours

Step-by-step explanation:

Let's say the swimming pool is 12,000 gallons.

The flow rate of the cold water pipe is:

12000 gal / 4 hr = 3000 gal/hr

The flow rate of the hot water pipe is:

12000 gal / 6 hr = 2000 gal/hr

If the cold water pipe is turned on for three hours, the volume of water is:

3000 gal/hr × 3 hr = 9000 gal

That leaves 3000 gallons.  The time to fill the rest of the pool with both the cold and hot water pipes is:

3000 gal / (3000 gal/hr + 2000 gal/hr) = 0.6 hr

It takes 0.6 hours (36 minutes).

Answer 2

If cold water pipe is turned on and hot water pipe is turned on 3 hours later then it will take 36 minutes (or 0.6 hr) to them to fill the pool together.

Step-by-step explanation:

Given :

Cold water pipe can fill a swimming pool in 4 hours, and a hot water pipe in 6 hours.

Solution :

Let's say the swimming pool is x gallons.

The flow rate of the cold water pipe is,

$\rm \dfrac{x}{4}\;gal/hr$

The flow rate of the hot water pipe is,

$\rm \dfrac{x}{6}\;gal/hr$

If the cold water pipe is turned on for three hours, the volume of water is:

$\rm \dfrac{x}{4} gal/hr\times 3 hr = \dfrac{3x}{4} \;gal$

The time to fill the rest of the pool with both the cold and hot water pipes is,

$\rm \dfrac{\dfrac{x}{4}}{\dfrac{x}{4}+\dfrac{x}{6}}= \dfrac{1}{4}\times \dfrac{24}{10}\;hr$

= 0.6 hr

If cold water pipe is turned on and hot water pipe is turned on 3 hours later then it will take 36 minutes (or 0.6 hr) to them to fill the pool together.

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https://brainly.com/question/7359669?referrer=searchResults