Lily is saving up to buy a cellphone. She needs to save at least $300 before she is able to buy the phone. Her grandfather gives her $40, and she earns $65 tutoring after school each week. Write an inequality for the number of weeks Lily will need to save to have at least $300, and describe the solution
Let w be the number of weeks Lily needs to save.
The inequality that represents the number of weeks Lily will need to save is 65w + 40 ≥ 300.
To solve the inequality, we subtract 40 from both sides: 65w + 40 - 40 ≥ 300 - 40
This simplifies to 65w ≥ 260.
Next, we divide both sides by 65 to isolate w: 65w/65 ≥ 260/65
This simplifies to w ≥ 4.
The solution to the inequality is that Lily will need at least 4 weeks to save at least $300.