Which expressions are equivalent to −2.1 (−5.9) (−3.7)−2.1 (−5.9) (−3.7) ? select each correct answer.
a. −(2.1 5.9) (−3.7)−(2.1 5.9) (−3.7)
b. −2.1−(5.9 3.7)−2.1−(5.9 3.7)
c. −(2.1−5.9) (−3.7)−(2.1−5.9) (−3.7)
d. −(2.1 5.9 3.7)

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?