2. Create a linear or exponential equation relating the cost [tex]\(C\)[/tex] and the number of months [tex]\(x\)[/tex] since July for each scenario:

a. The cost of a gallon of milk was [tex]\(\$2.00\)[/tex] in July, and increased by [tex]\(6.1\%\)[/tex] per month.
[tex]\[
C = 2.00(1 + 0.061)^x
\][/tex]

b. The cost of a gallon of milk was [tex]\(\$2.00\)[/tex] in July, and increased by [tex]\(\$0.138\)[/tex] per month.
[tex]\[
C = 2.00 + 0.138x
\][/tex]

c. Use your equations to predict the cost of a gallon of milk next July, a year later.

- Linear prediction: [tex]\(\$3.66\)[/tex]
- Exponential prediction: [tex]\(\$10.47\)[/tex]



Answer :

Certainly! Let's tackle each part of the question with detailed, step-by-step explanations.

### Scenario a: Exponential Growth

1. Initial Information:
- Initial cost of a gallon of milk: [tex]$2.00 - Monthly increase rate: 6.1% (which is 0.061 in decimal form) 2. Exponential Equation to Model the Cost Over Time: - The general form of an exponential growth equation is \(C = C_0 (1 + r)^x\), where: - \(C\) is the cost after \(x\) months. - \(C_0\) is the initial cost. - \(r\) is the monthly rate of increase. - \(x\) is the number of months. - Substituting the given values, we have: \[ C = 2.00 (1 + 0.061)^x \] ### Scenario b: Linear Growth 1. Initial Information: - Initial cost of a gallon of milk: $[/tex]2.00
- Monthly increase amount: [tex]$0.138 2. Linear Equation to Model the Cost Over Time: - The general form of a linear growth equation is \(C = C_0 + mx\), where: - \(C\) is the cost after \(x\) months. - \(C_0\) is the initial cost. - \(m\) is the monthly increase amount. - \(x\) is the number of months. - Substituting the given values, we have: \[ C = 2.00 + 0.138x \] ### Predicting the Cost After 12 Months: Next, we'll use both equations to predict the cost of a gallon of milk 12 months from July, which means \(x = 12\). #### For the Exponential Growth Equation: \[ C_{\text{exponential}} = 2.00 (1 + 0.061)^{12} \] After evaluating the expression, we know the cost after 12 months will be: \[ C_{\text{exponential}} = 4.070189245918128 \approx 4.07 \] So, the predicted cost of a gallon of milk in July (a year later) using the exponential model is approximately \$[/tex]4.07.

#### For the Linear Growth Equation:

[tex]\[ C_{\text{linear}} = 2.00 + 0.138 \times 12 \][/tex]

After evaluating the expression, we know the cost after 12 months will be:
[tex]\[ C_{\text{linear}} = 2.00 + 1.656 = 3.656 \approx 3.66 \][/tex]

So, the predicted cost of a gallon of milk in July (a year later) using the linear model is approximately \[tex]$3.66. ### Summary - Linear Prediction: \$[/tex]3.66
- Exponential Prediction: \$4.07