Question

the alexander family and jenkins family each used their sprinklers last summer. the water output rate for the alexander familys sprinkler was 20 L per hour. theh water output rate fro the jenkins familys sprinkler was 25 L per hour. the familes used their sprinklers for a combined total of 65 hours, resulting in a total water output of 1450 L. How long was each sprinkler used?

Answer 1

Answer:
Alexanders family sprinkler used for 35.25 hours
And the Jenkins family sprinkler was used for 29.75 hours.

Explanation:

Lets start with 2 assumptions, what if we only used the Alexander's family sprinklers, We can define X as the variable

`20x=1450`

`x= 72.5`
If we just used the Alexanders it would of took 72 hours and 30 minutes.

Now lets look at the Jenkins family sprinkler, lets define it as Y.

`25y=1450`

`y = 58`
With only the Jenkins it would of took 58 hours.

Now, if they just of shared the work equally among the two sprinklers, the Alexanders family doing 725 L and the Jenkins with the other half.
It would of took the Alexanders

`20x= 725`

`x=36.25`

Jenkins

`25y=725`

`y=29`

Making it a combined time of 65.25 hours. 15 minutes long of our 65 hour time.

Now the Jenkins sprinkler generates 5 more L than Alexanders per hour. Which means it would only take the Jenkins family 1 hours to make 25 liters but Alexanders would take
`(5)/(4)` hours. We know that 1 hour contains 60 minutes, which means
`(1)/(4)` of a hour contains 15 minutes.

So it would take Alexanders family sprinkler 15 minutes more to produce the same amount per hour that the Jenkins does.

So from this we can conclude that if the Jenkins family sprinkler was used more we can cut the extra 15 minutes off, making the answer That the

Alexanders family sprinkler used for 35.25 hours
And the Jenkins family sprinkler was used for 29.75 hours.