A recipe calls for 8 cups of Graham crackers and 1 1/2 cup of melted butter for 4 pie crust. How much a bottle will she need to make 2 pie crust

b). 4320 have a nice day

in counting the number of heads in 4 coin flips, the probability that we get exactly one head is the probability that we get anyone of the following 4 outcomes: httt, thtt, ttht, or ttth. each has probability 1/16, so the probability to get exactly one head in 4 flips is 1/16 + 1/16 + 1/16 + 1/16 = 4/16 = 1/4.