If s represents the number of songs Kim downloads, her expenses for a month must satisfy the inequality
5.00 + 0.58·s ≤ 13.00
To solve this, subtract 5.00 to get the s-term by itself, then divide by the coefficient of s.
0.58·s ≤ 8.00
s ≤ 8.00/0.58 ≈ 13.79
The number of songs must be an integer, so we conclude Kim can download 13 songs, but not 14 songs.
Kim can download 13 songs without exceeding her budget.
Investment: cost of her education + salary as sales clerk during two years
Investment = 18,000 (2) + 20,000 = 36,000 + 20,000 = 56,000
Time to recover investment = 56,000/35,000 = 1.6
In less than two years, after she starts to work Niah will have recoverd her investment.
The answer to your question is 92
f^-1(x)=(x-3)/4 is the inverse function f(x)=y=>y=4x+3 because f(x) is another way of writing y