The correct answer is:
At most 5.
Explanation:
The monthly fee is $25 and the charge for data is $10 per gigabyte. This means that the total monthly charges will depend on the number of gigabytes; this makes the gigabytes the independent variable. We use x to represent the independent variable.
Since data is $10 per gigabyte, and x is the number of gigabytes, this gives us 10x. We add to that the monthly fee of $25, for 10x+25.
We want to know how much they can download and pay at most 75; this means less than or equal to, and gives us the inequality
10x+25 ≤ 75
To solve this, subtract 25 from each side:
10x+25-25 ≤ 75-25
10x ≤ 50
Divide both sides by 10:
10x/10 ≤ 50/10
x ≤ 5
The maximum number of gigabytes that can be downloaded for this cost is 5.
