Question

A cell phone company charges a flat fee plus an additional charge per minute. If the graph contains the points (0,15)
and (50,90)
, what is the fee the company charges per minute? Give your answer in exact change.(1 point)
The charge per minute is $
.

Answer 1

To determine the charge per minute, we can use the two points provided: (0, 15) and (50, 90).

**Step 1: Identify the points**
- The first point (0, 15) means that when no minutes are used, the total charge is $15, which is the flat fee.
- The second point (50, 90) means that when 50 minutes are used, the total charge is $90.

**Step 2: Set up the equations**
We can express the total charge \( C \) as:
\[
C = F + r \cdot m
\]
where:
- \( C \) = total charge
- \( F \) = flat fee (which we know is $15 from the first point)
- \( r \) = charge per minute (which we need to find)
- \( m \) = number of minutes

From the first point (0, 15):
\[
15 = F
\]

From the second point (50, 90):
\[
90 = F + r \cdot 50
\]

**Step 3: Substitute \( F \) into the second equation**
Now, substitute \( F = 15 \):
\[
90 = 15 + r \cdot 50
\]

**Step 4: Solve for \( r \)**
\[
90 - 15 = r \cdot 50
\]
\[
75 = r \cdot 50
\]
\[
r = \frac{75}{50}
\]
\[
r = 1.5
\]

Thus, the charge per minute is \( r = 1.5 \).

**Final Answer:**
The charge per minute is $1.50.