Luca wants to refill a small pond that lost some water through evaporation. The pond has 10 gallons of water in it before Luca uses a hose to fill it up. The pond fills at a rate of 8 gallons per minute. Suppose that [tex]$y$[/tex] is the amount of water in the pond after [tex]$x$[/tex] minutes. Which equation could be graphed to help Luca find out how much water is in the pond at any time?

A. [tex]$y = 8x + 10$[/tex]
B. [tex][tex]$y = 8x$[/tex][/tex]
C. [tex]$y = 10x + 8$[/tex]
D. [tex]$y = 8x - 10$[/tex]



Answer :

To determine the correct equation that represents the amount of water in the pond after a certain number of minutes, let's break down the problem step-by-step.

1. Initial Condition:
- The pond initially has 10 gallons of water.

2. Filling Rate:
- The rate at which the pond is being filled is 8 gallons per minute.

3. Formulating the Equation:
- Let [tex]$x$[/tex] be the number of minutes.
- After [tex]$x$[/tex] minutes, the amount of water added to the pond can be calculated as [tex]\(8x\)[/tex] gallons (since water is being added at a rate of 8 gallons per minute).
- Therefore, the total amount of water in the pond after [tex]$x$[/tex] minutes will be the initial amount plus the amount added.

So, we can write the total amount of water [tex]\(y\)[/tex] as:
[tex]\[ y = 10 + 8x \][/tex]

Simplifying this, we get:
[tex]\[ y = 8x + 10 \][/tex]

This equation represents the total amount of water in the pond after [tex]$x$[/tex] minutes.

Therefore, the correct equation from the given options is:
- [tex]$y = 8x + 10$[/tex]

The other options are:
- [tex]$y = 8x$[/tex] (Incorrect because it does not account for the initial 10 gallons)
- [tex]$y = 10x + 8$[/tex] (Incorrect because the rate and initial amount are incorrectly placed)
- [tex]$y = 8x - 10$[/tex] (Incorrect because it subtracts the initial amount rather than adding it)

Thus, the correct equation is:
- [tex]$y = 8x + 10$[/tex]