SOLUTION: I need your help with my homework. A spinning device have 3 numbers, 1, 2, and 3, each as likely to turn up as the other. If the device is spun twice, what is the probability th

Algebra ->  Probability-and-statistics -> SOLUTION: I need your help with my homework. A spinning device have 3 numbers, 1, 2, and 3, each as likely to turn up as the other. If the device is spun twice, what is the probability th      Log On


   



Question 247653: I need your help with my homework.
A spinning device have 3 numbers, 1, 2, and 3, each as likely to turn up as the other. If the device is spun twice, what is the probability that:
a)The same number turns up both times?
b)The sum of the numbers turning up to 5?
Thank very much.

Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
Assuming the device is fair, each of the 3 numbers has the same probability as the others: 1/3.
.
Each spin is independent, which means it does not depend on others.
.
What the possibilities for two spins?
1 & 1
1 & 2
1 & 3
2 & 1
2 & 2
2 & 3
3 & 1
3 & 2
3 & 3
.
a) The probability that the same number turns up twice in a row.
3/9 = 1/3
b ) The sum of the numbers totals 5.
How many total 5?
2
So the probability is 2/9.