Question

Your company gives you a cell phone plan which allows you 600 minutes to talk per month. So far this month, you have used 330 minutes and you have 10 days left on this month's plan. Which inequality could you use to determine how many minutes at most you can use per day so that you don't go over your monthly plan minutes?
A.)10x+330≥600

B.)10x+330>600

C.)10x+330≤600

D.)10x+330<600

Answer 1

The answer is C) 10x + 330 ≤ 600. 
We use the ≤ since you are allowed to use the 600th minute.
When we subtract 330 from both sides, it makes a bit more sense
10x ≤ 270
270 is the number of minutes left your plan since you've already used 330, and you have 10 days left in the month.