a)
Let c be the number of right guesses.
the probability of c answers =.25 and probability of the wrong answer is 1-.25=.75
c distribution is in the parameter of (20, .25).
b) mean = 20 * .25== 5
c) p of c guess =.25 ^20 =9.095* 10 ^-13
d) p of 10 c guess =.014 or 1.4% it is not possible for him to have 10 right guess.
