Question 295889
Let x = probability that San Francisco will play in the next Super Bowl.
Let y = probability that San Francisco will not play in the next Super Bowl.


The probability that San Francisco will play in the next Super Bowl is 9 times the probability that they won't plan in the next Super Bowl.


This means the x = 9*y


You also know that probability that San Francisco will play in the next Super Bowl plus the probability that San Francisco will not play in the next Super Bowl is equal to 1.


This means that x + y = 1


Since x = 9*y, you can substitute in this equation to get:


9*y + y = 1


Combine like terms to get 10*y = 1


Divide both sides of this equation to get y = .1


Since x = 9 * y, this means that x = 9 * .1 = .9


You get x = .9 and y = .1


This means that the probability that San Francisco will play in the next Super Bowl is .9 and the probability that San Francisco will not play in the next Super Bowl is .1.


.9 is 9 * .1.
.9 + .1 = 1