2. Peter is a door-to-door sales representative who makes a sale at only 8% of his house calls. If Peter makes 219 house calls today, what is the probability that:

(a) he makes a sale at 12 or fewer houses?

Someone was trying to help me and said 12 x 100/219 = 5.6% but I have no idea where the 100/219 comes into play.

(b) he makes a sale at 20 or fewer houses?

(c) he makes a sale at 15 to 25 houses?