Answer:
(a) $62.92 saved in 25 weeks
(b) 41 weeks to save $100
Step-by-step explanation:
Given
[tex]y = 2.92 + 2.4x[/tex]
[tex]x \to weeks[/tex]
[tex]y \to savings[/tex]
Solving (a): Savings in 25 weeks.
This means that: x = 25
So:
[tex]y = 2.92 + 2.4x[/tex]
[tex]y = 2.92 + 2.4 * 25[/tex]
[tex]y = 2.92 + 60[/tex]
[tex]y = 62.92[/tex]
Solving (b): Whole weeks to save $100
This means that x = 100
So:
[tex]y = 2.92 + 2.4x[/tex]
[tex]100 = 2.92 + 2.4x[/tex]
Collect like terms
[tex]2.4x = 100 - 2.92[/tex]
[tex]2.4x = 97.08[/tex]
Solve for x
[tex]x = 97.08/2.4[/tex]
[tex]x = 40.45[/tex]
Round up
[tex]x = 41[/tex]