Answer:
<em>She will take 10 weeks to save the money for the DVD player</em>
Step-by-step explanation:
Let w = Lianne's weekly allowance.
The DVD player costs 2 1/2 times her weekly allowance, thus
DVD cost = 5/2w
She gets w every week but spends 3/4w on other things, thus the remaining money is
Weekly savings =w - 3/4w = 1/4w
To know the number of weeks needed, we divide the DVD cost by the weekly savings:
Operating:
N = 10
She will take 10 weeks to save the money for the DVD player