Super Bowl Contender: prob. of playing is 9X prob. of not

[angel716]

The probability that San Francisco plays in the next Superbowl is nine times teh probability that they do not play in the next Super Bowl. The probability that San Francisco plays in the next Super Bowl plus the probablility that they do not play is 1. What is the probability that San Francsico plays in the next Super Bowl?

now this one I just can' t get pass P=9 but that P=9w and that from my understanding it equals all up to 1
p=9+1w=9 is this how it would read and then place 9 on both sides

(9)9+1w=(9)
81+1w=9
p=9

take 81 and divide it by 9 p=9 is my guess.

 

[Mrspi]

Re: Super Bowl Contender

The probability that San Francisco plays in the next Superbowl is nine times teh probability that they do not play in the next Super Bowl. The probability that San Francisco plays in the next Super Bowl plus the probablility that they do not play is 1. What is the probability that San Francsico plays in the next Super Bowl?

now this one I just can' t get pass P=9 but that P=9w and that from my understanding it equals all up to 1
p=9+1w=9 is this how it would read and then place 9 on both sides (9)9+1w=(9)
81+1w=9
p=9
take 81 and divide it by 9 p=9 is my guess.

let x = probability that they play
let y = probability that they don't play

you're told that the two probabilities must add up to 1, so
x + y = 1

You're also told that the probability that they play is 9 times the probability that they don't play. So,
x = 9y

Ok...you have a system of two equations in two variables:
x + y = 1
x = 9y

Can you solve that system? And, remember that you're asked for the probability that they DO play, so the value of x will be the answer to the question.