Question

Bookstore rents books to students for $2 per book. The cost of running the bookstore is $300 per hour. The numbers of books and the probabilities that the bookstore would rent them in an hour mimics the distribution of the outcomes of flipping four coins. The probability of renting a number of books was observed to be the same as the number of heads that appear in a four-coin flip. This distribution is represented in the table.
Books Rented Probability









Based on the data in the table, the expected value the bookstore can make per student in one hour is $

Answer 1

From my research, the available data in the problem is as follows:

No. of Heads | Probability
          0               1/16
          1               4/16
          2               6/16
          3               4/16
          4               1/16

To calculate the average amount spent by a student in an hour:

[(0 * 1/16) + (1 * 4/16) + (2 * 6/16) + (3 * 4/16) + (4 * 1/16)] * 2

= 4

Therefore, the library earns $4 per student each hour