Question

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Linear Functions in Context Practice
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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 find the charge per minute, we can use the two points provided: (0, 15) and (50, 90).

1. The point (0, 15) indicates that when no minutes are used (0 minutes), the charge is $15. This is the flat fee.
2. The point (50, 90) indicates that when 50 minutes are used, the charge is $90.

Next, we can set up the equation representing the relationship between the total charge (y) and the number of minutes (x):

\[
y = mx + b
\]

Where:
- \(m\) is the charge per minute.
- \(b\) is the flat fee.

From the point (0, 15), we have \(b = 15\). Therefore, the equation becomes:

\[
y = mx + 15
\]

We can now substitute the second point (50, 90) into this equation to solve for \(m\):

\[
90 = m(50) + 15
\]

Now, subtract 15 from both sides:

\[
90 - 15 = m(50)
\]
\[
75 = 50m
\]

Next, divide both sides by 50 to solve for \(m\):

\[
m = \frac{75}{50} = \frac{3}{2} = 1.50
\]

Thus, the charge per minute is:

\[
\text{The charge per minute is } \$1.50
\]

Therefore, the final answer is:

The charge per minute is $1.50.