An ice cream stand reports that 12% of the cones they sell are "jumbo" size. You want to see what a "jumbo" cone looks like, so you stand and watch the sales for a while. What is the probability that the first jumbo cone is the fourth cone you see them sell?
A) 33%
B) 60%
C) 40%
D) 8%
E) 93%

Question

Quizplus · Accepted Answer

The probability of seeing a jumbo cone on any given sale is 0.12, and the probability of not seeing a jumbo cone is 0.88. To calculate the probability of seeing the first jumbo cone on the fourth sale, we need to multiply the probability of not seeing a jumbo cone on the first three sales (0.88 x 0.88 x 0.88) by the probability of seeing a jumbo cone on the fourth sale (0.12). This gives us 0.088, or 8% chance of the first jumbo cone being the fourth sale we see.

An Ice Cream Stand Reports That 12% of the Cones