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Problem: A computer shop charges 20 pesos per hour (or a fraction of an hour) for the first two hours and an additional 10 pesos per hour for each succeeding hour. Represent your computer rental fee using the function R(t) where t is the number of hours you spent on the computer.

My answer: $$R(t) = \cases{20 \text{ pesos} & if $0 <t\le 2$\cr ({t-2}) \cdot 10 \text{ pesos} +40 \text{ pesos} & if $t>2$}$$

Please correct me if I have any mistake.

Janine
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If i understand you the right way, it should be $ R \colon \Bbb{N} \to \Bbb{N} $

$$R(t) = \cases{20 {t} & if $0 \le t \le 2$\cr 10({t-2}) +40 & if $t>2$}$$ where $R(t)$ is in pesos. However this can be a misunderstanding of your first sentence. I think your mistake then would be that he charges 20 pesos per hour in the first two hours that would be 20 pesos each and a total of 40 pesos for two hours.

  • The problem above is exactly the same problem written on my textbook. I thought about what you said too. The first sentence confuses me. – Janine Jun 18 '17 at 12:35
  • Okay, so i am pretty sure that its 20 pesos times t. Further should your function only allow integer values or should it be a function of real numbers? Am i allowed to evaluate $R(1.5)$? –  Jun 18 '17 at 12:37