A piggy bank contains only nickels, dimes and quarters. Given the following information, create a system of equations to determine how many of each type of coin are in the bank.
 The coins total $4.50
 There are 32 coins in the bank
 The number of nickels and dimes together is 8 more than the number of quarters.
someone please help

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?