Tony and Caroline are trying to solve the following system. Tony says to multiply the first equation by 4. Caroline says to multiply the first equation by 2. Which student's first step will work toward eliminating a variable? A:Only Tony's idea will work toward eliminating a variable.
B:Only Caroline's idea will work toward eliminating a variable.
C:Neither of these will work.
D:BOTH ideas will work toward eliminating a variable.

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?