The cost of cheese at three stores is a function of the weight of the cheese. The cheese
is not prepackaged, so a customer can buy any amount of cheese.
• Store A sells the cheese for a dollars per pound.
.
Store B sells the same cheese for b dollars per pound and a customer has a coupon
for $5 off the total purchase at that store.
• Store C is an online store, selling the same cheese at c dollar per pound, but with a
$10 delivery fee.
This graph shows the price functions for stores A, B, and C.

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?