Question

Gil buys 4 books for $16. Then he sells 3 CDs for $27. Write equations for y, Gil’s change in money after buying a book, and for x, his change in money after selling a CD, in standard form. What is the slope of each equation?

Answer 1

Given:

Gil buys 4 books for $16. Then he sells 3 CDs for $27.

To find:

The equations for y, Gil’s change in money after buying a book, and for x, his change in money after selling a CD, in standard form.

Slope of each equation.

Solution:

Gil buys 4 books for $16.

4 books = $16

1 book = $4

Let n be the number of book purchased, then change in money after buying n book is

$y=-4n$

Here, negative sign represents decrease in money. Here, slope of -4 it means the money decreased by $4 after buying each book.

He sells 3 CDs for $27.

3 CDs =$27

1 CDs =$9

Let c be the number of CDs sold, then change in money after selling m CDs is

$x=9m$

Here, slope of 9 it means the money increased by $9 after selling each CD.