Answer:
14.28 < h < 15
She can and would need to work 14.28 hours.
Explanation:
To find how many hours she needs to work to earn $100, we need to know how much she is paid per hour. This amount is x because it is unknown. So 12 hours at x rate equals 84. This is 12x=84 so x=$7 per hour.
To earn a 100, she will earn $7 a hour but not work more than 15 hours. So we write the equation 100=7h where h is number of hours. Solve and h = 14.28. So Sylvia must work 14.28 < h < 15 to earn 100.