Chapter 8.1, Problem 5GP

To determine

To write an equation that represents the difference in the monthly sales of smartphones and the monthly sales of gaming consoles, and then predict the difference in monthly sales in 24 months.

Answer to Problem 5GP

  $D\left(m\right)=3m+59$, $D\left(24\right)=\text{131}$ .

Explanation of Solution

Given:

The number of smartphones $P$ and the number of gaming consoles $C$ sold in m months in an electronic store are given by $P=7m+137$ and $C=4m+78$ respectively.

Calculation:

The equation representing the difference in the monthly sales of smartphones and the monthly sales of gaming consoles in m can be given as follows:

  $\begin{array}{c}D\left(m\right)=\left(7m+137\right)-\left(4m+78\right)\\ =3m+59\end{array}$

Therefore, the difference in monthly sales in 24 months is:

  $\begin{array}{c}D\left(24\right)=3\cdot 24+59\\ =72+59\\ =\text{131}\end{array}$