A slot machine has three wheels that spin independently. So, when one plays this
ID: 3331902 • Letter: A
Question
A slot machine has three wheels that spin independently. So, when one plays this machine, on the computer screen each wheel will display one symbol, that is, one will see three symbols side by side. Each wheel can display any of the 10 equally likely symbols: four of the symbols are bars, three of the symbols are lemons, two of the symbols are cherries and one of the symbols is a bell.
a) What is the probability of getting 3 lemons, that is, LEMON, LEMON, LEMON?
b) What is the probability of getting no fruit symbols?
c) What is the probability of getting three bells? (JACKPOT!)
d) What is the probability of getting no bells?
e) What is the probability of getting at least one bar? (Losing Play)
Explanation / Answer
a) P(Lemon) = 3/10
P(3 lemons) = 3/10 x 3/10 x 3/10 = 0.027
b) P(no fruit fruit symbo) = (10 - 3 - 2)/10 = 1/2
P(no fruit symbols) = 1/2 x 1/2 x 1/2 = 0.125
c) P(3 bells) = 1/10 x 1/10 x 1/10 = 0.001
d) P(no bells) = 9/10 x 9/10 x 9/10 = 0.729
e) P(a least 1 bar) = 1 - P(no bars)
= 1 - (6/10 x 6/10 x 6/10)
= 0.784