Chapter 2.2, Problem 34PPSE

Solution

How much more will it cost to make a 30-minute local call?

The local call cost is dependent variable.

The 30-minute call cost 49.4 cents more cost than the base 4-minute call price.

Given:

The 4-minute local call cost 7.6 cents.

Calculation:

The 4-minute local call costs 7.6 cents, which can be represented as:

  $4\min \to 7.6\text{cents}$

The 1-minute local call costs:

  $1\min \to \frac{7.6}{4}\text{cents}$

The 30-minute local call costs:

  $\begin{array}{l}30\min \to \frac{7.6}{4}\times 30\text{cents}\\ 30\min \to \frac{7.6}{2}\times 15\text{cents}\\ 30\min \to 3.8\times 15\text{cents}\\ 30\min \to 57\text{cents}\end{array}$

The more it will cost than the base 4-minute call price is:

  $57-7.6=49.4$

Therefore, the 30-minute call cost 49.4 cents more cost than the base 4-minute call price.

Here, the local call cost is dependent variable.

The 30-minute call cost 49.4 cents more cost than the base 4-minute call price.