Question

Greg is thinking of a number n, and he wants his sister to guess the number. His first clue is that three less than two times his number is at least five and at most seven. Write a compound inequality that shows the range of numbers that Greg might be thinking of.

Answer 1

2n - 3 ≥ 5

Add 3 to both sides.

2n ≥ 8

Divide both sides by 2

n ≥ 4

That's the first part of our inequality. Let's get the second part.

2n - 3 ≤ 7

Add 3 to both sides.

2n ≤ 10

Divide both sides by 2

n ≤ 5

Our compound inequality is: 4 ≤ n ≤ 5