The Price of a Good Is the Y-Variable and the Quantity

Multiple Choice

The price of a good is the y-variable and the quantity of a good that people want to buy is the x-variable. When the price of a hamburger increases from $10 to $12, the quantity of hamburger that people want to buy in a day decreases from 20 to 16. What is the slope of the line that describes the relationship between price and the quantity of hamburgers that people want to buy?

A) -1/2
B) -2
C) -10
D) 5