Question

A store sells cooking oil of two different brands in bottles of the same size. The table below and the equation each show the price (y), in dollars, of different number of bottles of oil (x):
Brand A
Number of Bottles, x Price (dollars), y
2
24
3
36
4
48
5
60


Brand B
y = 15x

How many dollars more is the price of 9 bottles of brand B oil than the price of 9 bottles of brand A oil?
$3
$9
$18
$27

Answer 1

Using the data, we can calculate the price per bottle for Brand A, which is:
24 / 2
= $12 per bottle

We also know that the slope of a line shows the rate of change, so the price per bottle for Brand B is $15. 

The difference per bottle is 15 - 12 = Brand B is cost $3 more per bottle
The difference for 9 bottles will be: 9 * 3 = $27.