Answer:
16 weeks
Explanation:
Given:
Amount saved each week in the first 5 weeks = $25
Amount saved each week in the next 7 weeks = $25 + $20 = $45
Amount saved each week afterwards = $25
Total amount to be saved = $540
Now,
The total amount saved in the first 5 weeks = $25 × 5 = $125
The total saved in the next 7 weeks = $45 × 7 = $315
Thus,
The total amount saved till now = $125 + $215 = $440
Now,
The remaining amount to be saved = $540 - $440 = $100
The time required to save the $100 = [tex]\frac{\textup{100}}{\textup{25}}[/tex]
= 4
Hence,.
the total weeks required = 5 + 7 + 4 = 16 weeks