Let e = Emily's age and m = Mary's age.

We have the equation e = 2m + 3 and the inequality e + m < 30

Substitute the equation for e into the inequality:

2m + 3 + m < 30

Add the m terms

3m + 3 < 30

Subtract 3 from each side of the inequality

3m < 27

Divide each side of the inequality by 3 to isolate m

m < 9

Therefore, the

**greatest age**Mary could be is 8, since less than 9

__does not include__9.