a. Sarita signed up with Netflix for a fixed fee of $16.99 per month. For this fee, she can receive up to 3 DVDs at a time in the mail and exchange each DVD as often as she likes. She also receives unlimited instant access to movies being streamed from Netflix to her computer or TV. During the average month in 2010, Sarita received and watched 6 movies sent to her through the mail and she watched an additional 13 movies which were streamed to her computer. What is the average cost of a movie to Sarita? What is the marginal cost of an additional movie?
b. The principal of Hamilton High School found that requiring those students who were failing algebra to attend an after- school tutoring program resulted in a 30 percent average increase in their algebra grades. Based on this success, the principal decided to hire more tutors and require that all students must attend after-school tutoring, so everyone's algebra grades would improve.
c. People who drive hybrid automobiles recycle their trash more than people who do not drive hybrids. Therefore, recycling trash causes people to drive hybrid automobiles.