Question

A​ long-distance telephone company charges a rate of 9 cents per minute or a 70​-cent minimum charge per completed​ call, whichever is greater. Find the​ cost, in cents per​ minute, for a 5​-minute call.

Answer 1

To determine the cost of a 5-minute call, we need to calculate both the cost per minute and the minimum charge.

1. **Calculate the cost based on the per-minute rate**:
\[
\text{Cost for 5 minutes} = 5 \text{ minutes} \times 9 \text{ cents/minute} = 45 \text{ cents}
\]

2. **Compare with the minimum charge**:
The minimum charge per completed call is 70 cents.

3. **Determine the greater cost**:
- Cost based on per-minute rate: 45 cents
- Minimum charge: 70 cents

Since 70 cents (minimum charge) is greater than 45 cents, the cost for the 5-minute call will be 70 cents.

Thus, the final cost for the call is **70 cents**.

If we were to express this in cents per minute for the 5-minute call:
\[
\text{Cost per minute} = \frac{70 \text{ cents}}{5 \text{ minutes}} = 14 \text{ cents per minute}
\]

Therefore, the cost in cents per minute for a 5-minute call is **14 cents per minute**.