Clara is growing her hair out and wants it to be no longer than 15 cm but more than 11 cm. Her hair is 7 cm right now and grows at a rate of 0.25 cm per week. The compound inequality
11 < 7 + 0.25t ≤ 15 models the scenario.
Assuming you are asking how many weeks, than the answer would be 17-32, because at 16 weeks the growth would be 4 cm, totaling at 11, but you need more than 11cm, and at 32 weeks it's at 15 cm.
