Question

Lucy's goal for her cycling class at the gym is to burn 450 calories in one hour. The number of calories (c) she actually burns in one hour varies no more than 45 calories. Which inequality below represents this scenario?
Answer
|c - 450| <= 45
|c + 450| >= 45
|c - 45| <= 450
|c - 45| >= 450

5 points

Answer 1

So c is within 45 of 450, right? So what can c be? It can be up to 495 or as low as 405. Plug those values in to the inequalities and see if they work.
Like for the last one |c-45| >= 450
plug in 495 gives 450>=450, but plugging in 405 gives |405-45| >= 450 which is false.