Describing a Real-World Linear Equation

A tank filled with 50 quarts of water empties at a rate of 2.5 quarts per minute. Let [tex][tex]$w$[/tex][/tex] be the quarts of water left in the tank and [tex][tex]$t$[/tex][/tex] be the time in minutes.

\begin{tabular}{|c|c|}
\hline
Time [tex]$(t)$[/tex] & Quarts of water [tex]$(w)$[/tex] \\
\hline
0 & 50 \\
\hline
2 & 45 \\
\hline
4 & 40 \\
\hline
\end{tabular}

Choose the correct answers:

1. Which equation models the relationship?
2. Is there a viable solution when time is 30 minutes?



Answer :

Let's break down the problem step-by-step:

1. Identify the Rate of Water Emptying:
We start by determining the rate at which the water is emptying from the tank. We are given the following data points:

Time [tex]\( t \)[/tex] (in minutes) | Quarts of water [tex]\( w \)[/tex]
--------------------------|------------------------
0 | 50
2 | 45
4 | 40

From these points, we can see that for every increase in 2 minutes, the water in the tank decreases by 5 quarts:
[tex]\[ \text{Rate} = \frac{(50 - 45)}{(2 - 0)} = \frac{5 \text{ quarts}}{2 \text{ minutes}} = 2.5 \text{ quarts per minute} \][/tex]

2. Formulate the Equation:
The water decreases at a constant rate. We can represent the amount of water left [tex]\( w \)[/tex] in the tank as a function of time [tex]\( t \)[/tex]. We know:
At [tex]\( t = 0 \)[/tex], [tex]\( w = 50 \)[/tex]
The rate of water emptying is 2.5 quarts per minute.

This gives us a linear equation:
[tex]\[ w = 50 - 2.5t \][/tex]

3. Verify the Equation:
Let’s verify the equation with another data point:
At [tex]\( t = 2 \)[/tex]:
[tex]\[ w = 50 - 2.5 \times 2 \][/tex]
[tex]\[ w = 50 - 5 = 45 \][/tex]

At [tex]\( t = 4 \)[/tex]:
[tex]\[ w = 50 - 2.5 \times 4 \][/tex]
[tex]\[ w = 50 - 10 = 40 \][/tex]

Both points match the given data, confirming our equation is correct.

4. Check the Solution for [tex]\( t = 30 \)[/tex] Minutes:
Now, we need to determine if there is a viable solution when [tex]\( t = 30 \)[/tex] minutes:
[tex]\[ w = 50 - 2.5 \times 30 \][/tex]
[tex]\[ w = 50 - 75 \][/tex]
[tex]\[ w = -25 \][/tex]

Since the amount of water cannot be negative, this means there is no viable solution when [tex]\( t = 30 \)[/tex] minutes.

Summary:
- The equation modeling the relationship is:
[tex]\[ w = 50 - 2.5t \][/tex]

- There is no viable solution when the time is 30 minutes.