Begin by writing an equation that represents the average monthly cost of the Internet service provider. Let y be the average monthly cost and x be the number of months of service.
The competitor is a better choice for less than 18 months of service. See solution.
Practice makes perfect
We will begin by writing an equation that represents the average monthly cost of the Internet service provider. Let y be the average monthly cost and x be the number of months of service.
Verbal Expression
Algebraic Expression
Installation fee ($)
50
Fee for x months ($)
43 x
Total fee ($)
43 x+ 50
Average monthly cost is $y.
y=43 x+ 50/x
We now have the equation.
y=43x+50/x
Next, we will compare the average monthly cost of the Internet service provider and its competitor. Let's first find the average monthly cost of the Internet service provider for 6 months of service.
The average monthly cost is about $51.33 for 6 months of service. Proceeding in the same way, we can find the average cost for 12, 18, and 24 months of service.
Months, x
43x+50/x
Average monthly cost of the Internet service provider (dollars), y
Average monthly cost of the competitor (dollars), y
6
43( 6)+50/6
$51.33
$49.83
12
43( 12)+50/12
$47.17
$46.92
18
43( 18)+50/18
$45.78
$45.94
24
43( 24)+50/24
$45.08
$45.45
Interpreting the table, we can say that the competitor is a better choice for less than 18 months of service.
