Question

My cell phone company charges a flat flat feet plus an additional charge per minute if the graph contains the 0, 15 and 50, 90 what is the fee the company charges per minute

Answer 1

To determine the additional charge per minute based on the points given (0, 15) and (50, 90) on a graph of cost versus minutes, we can calculate the slope of the line that connects these two points.

1. **Identify the points:**
- Point A: (0, 15)
- Point B: (50, 90)

2. **Using the formula for slope (\(m\)):**
\[
m = \frac{y_2 - y_1}{x_2 - x_1}
\]
Where \((x_1, y_1) = (0, 15)\) and \((x_2, y_2) = (50, 90)\):

\[
m = \frac{90 - 15}{50 - 0} = \frac{75}{50} = 1.5
\]

The slope of the line represents the charge per minute. Thus, the company charges **$1.50 per minute**.

To confirm, we can also look at the total cost difference relative to the minutes:

- At 0 minutes, the cost is $15 (the fixed fee).
- At 50 minutes, the total cost is $90.

The total additional charge for 50 minutes is:
\[
90 - 15 = 75
\]

The charge per minute then is:
\[
\frac{75}{50} = 1.5
\]

Thus, the fee the company charges per minute is indeed **$1.50**.