A swimming pool starts with 600 gallons of water in it. It springs a leak, and is draining at a rate of 100 gallons per hour.

Next, record the change in the number of gallons of water. You can find the change in gallons of water by multiplying the change in gallons per hour by the number of hours. You can represent the number of hours with the variable t.
t
g
0
1
2
3
4
5
6
7
8
9
10
0
100
200
300
400
500
600
700
800
900
1,000
Time in hours
Gallons of water in the pool
Rate of change: -100
Initial amount: 600

Gallons of water in the pool = Initial number of gallons of water + Change in gallons
of water
g = 600 +

Change in gallons per hour Number of hours

1 answer

To express the number of gallons of water in the pool over time, we can use the formula you've given:

\[ g = 600 + \text{Change in gallons} \]

The change in gallons of water due to the leak can be calculated as follows:

\[ \text{Change in gallons} = \text{Change in gallons per hour} \times \text{Number of hours} = -100t \]

So we can substitute that into the equation for \( g \):

\[ g = 600 + (-100t) \]

This simplifies to:

\[ g = 600 - 100t \]

Now, we can calculate \( g \) for different values of \( t \) (the number of hours):

  • When \( t = 0 \): \[ g = 600 - 100(0) = 600 \]

  • When \( t = 1 \): \[ g = 600 - 100(1) = 500 \]

  • When \( t = 2 \): \[ g = 600 - 100(2) = 400 \]

  • When \( t = 3 \): \[ g = 600 - 100(3) = 300 \]

  • When \( t = 4 \): \[ g = 600 - 100(4) = 200 \]

  • When \( t = 5 \): \[ g = 600 - 100(5) = 100 \]

  • When \( t = 6 \): \[ g = 600 - 100(6) = 0 \]

  • When \( t = 7 \): \[ g = 600 - 100(7) = -100 \quad (\text{pool is empty}) \]

  • When \( t = 8 \): \[ g = 600 - 100(8) = -200 \]

  • When \( t = 9 \): \[ g = 600 - 100(9) = -300 \]

  • When \( t = 10 \): \[ g = 600 - 100(10) = -400 \]

Based on these calculations, we see how the number of gallons in the swimming pool decreases over time until it becomes empty (at \( t = 6 \) hours) and progressively goes negative, indicating the theoretical water level if the leak continues beyond the pool's capacity.

The table of values for \( t \) and \( g \) would look as follows:

| Time in hours (t) | Gallons of water (g) | |--------------------|-----------------------| | 0 | 600 | | 1 | 500 | | 2 | 400 | | 3 | 300 | | 4 | 200 | | 5 | 100 | | 6 | 0 | | 7 | -100 | | 8 | -200 | | 9 | -300 | | 10 | -400 |

This provides a complete representation of the rate at which the water in the pool decreases with time given the leak.