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 = 5

Step-by-step explanation:

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

6-4 = 2

2+3 = 5

5 answer

0.6 of an hour

Step-by-step explanation:

A cold pipe takes 4h hours so we can assume ¼ of our job is done in one hour.

After 3 hours go by with the cold pipe on, we have ¼ of the job left.

Now we have our hot pipe, which takes 6 hours for the entire pool, so we can assume that it has a rate of ⅙ per hour. Now since these two pipes are working together we can add them.

⅙ + ¼ = ⁵/₁₂

Now we divide.

Since at the start 3 hours had gone by with the cold pipe that would have been ¾ of our time so, 1 - ¾ = ¼

¼ ÷ ⁵/₁₂ = ⅗ or 0.6 of an hour

add all the numbers and check the ones place.

the answer is 486. as the ones place is more than 4, the estimation will be the next 10 ie, 490

explanation:

previous steps have made pa≅ pb ≅ st ≅ su. setting the compass width to ab allows you to make tu the same length. then δstu ≅ δpab by the sss congruence postulate, and ∠p ≅ ∠s by the reason cpctc.