Question

The phone company A Fee and Fee has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. If a customer uses 230 minutes, the monthly cost will be $116.5. If the customer uses 520 minutes, the monthly cost will be $218.

A) Find an equation in the form y=mx+b, where x is the number of monthly minutes used and y is the total monthly of the A Fee and Fee plan.

Answer: y=



Do not use any commas in your answer.

B) Use your equation to find the total monthly cost if 1000 minutes are used.

Answer: If 1000 minutes are used, the total cost will be
dollars

Answers

GPT-4o mini
Let's start by extracting the necessary information to find the equation.

We know that:

1. When \( x = 230 \) minutes, \( y = 116.5 \).
2. When \( x = 520 \) minutes, \( y = 218 \).

We can represent the monthly cost as a linear equation in the form \( y = mx + b \), where:
- \( m \) is the cost per minute,
- \( b \) is the flat monthly fee.

**A)** First, we’ll find \( m \) (the cost per minute) and \( b \) (the flat fee) using the two points we've been given.

From the points \( (230, 116.5) \) and \( (520, 218) \), we can set up the following equations:

1. \( 116.5 = m(230) + b \) (Equation 1)
2. \( 218 = m(520) + b \) (Equation 2)

Next, we can subtract Equation 1 from Equation 2 to eliminate \( b \):

\[
218 - 116.5 = m(520) - m(230)
\]

This simplifies to:

\[
101.5 = m(290)
\]

Now we solve for \( m \):

\[
m = \frac{101.5}{290} \approx 0.350
\]

Now that we have \( m \), we can substitute it back into either Equation 1 or Equation 2 to find \( b \). Using Equation 1:

\[
116.5 = 0.350(230) + b
\]
\[
116.5 = 80.5 + b
\]
\[
b = 116.5 - 80.5 = 36
\]

Thus, the equation is:

\[
y = 0.350x + 36
\]

**Final Answer for A:**

\[ y = 0.350x + 36 \]

---

**B)** Now we can use the found equation to calculate the total monthly cost if 1000 minutes are used.

Substituting \( x = 1000 \) into the equation:

\[
y = 0.350(1000) + 36
\]
\[
y = 350 + 36
\]
\[
y = 386
\]

Thus, if 1000 minutes are used, the total cost will be:

**Final Answer for B:**

The total cost will be 386 dollars.