Word problem..this one has me baffled and it is probably so simple.?

Question

The probability that San Francisco plays in the next Super Bowl is 9 times the probability that they do not play in the next Super Bowl. The probability that San Francico plays in the next Super Bowl plus the probability that they do not play is 1.
What is the probability that San Francisco plays in the next Super Bowl

Answer 1

Think of the probabilities as fractions. That's why the total (they either will or won't play) is 1. Call the probability that they won't play "x".

You have X + 9X = 1 or 10 X =1 So X is 1/10

The probability that they won't play is 1/10 or 1 out of 10.
The probability that they will play is 9/10 or 9 out of 10.

I wouldn't place any bets on this.

Answer 2

9 to 1

Answer 3

Probability = favorable outcomes / all outcomes.
So, Plays + Not Plays = 1
and Plays = 9* Not Plays

So (9*Not Plays) + Not Plays = 10*Not Plays = 1
Or- Not Plays = 0.1 (10 percent), Plays = 0.9 (90 percent)

Answer 4

Given

p(play) = 9p(don't play)
p(play) + p(don't play) = 1

Using substitution
p(play) + p(don't play) = 1
9p(don't play) + p(don't play) = 1
10p(don't play) = 1
p(don't play) = 1/10

p(play) + p(don't play) = 1
p(play) = 1 - p(don't play) = 1 - 1/10 = 9/10

Answer 5

let x=prob. that S.F. plays
let y=prob. that S.F. doesn't play
x=9*y

x+y=1
x=1-y

1-y=9*y

1=10y

y=1/10 or .1

x+y=1
x+.1=1
x=.9

90% probability

Answer 6

p = probability

9p (probability in SB) + p (probability not in SB) = 1

p = 0.1

9p = 0.9

====> 0.9 percent chance in superbowl

Answer 7

y=yes.......n=no
9n=y
n+y=9

n=9/10
y=1/10

Answer 8

Zero...