# Thread: A few questions, hoping somebody might be able to help out...

1. ## A few questions, hoping somebody might be able to help out...

Math has always been my weakest subject, and this year has been no different. Here's a few i need help with, if possible.

Carrie is a kicker on her rugby team. She estimates that her chances of scoring on a penalty kick during a game are 75% when there is no wind, but only 60% on a windy day. If the weather forecast gives a 55% probability of windy weather today, what is the probability of Carrie scoring on a penalty kick in a math this afternoon?

A four member curling team is randomly chosen from six grade 11 students and nine grade 12 students. What is the probability that the team has at least one grade 11 student?

2. Originally Posted by Desiderius
Math has always been my weakest subject, and this year has been no different. Here's a few i need help with, if possible.

Carrie is a kicker on her rugby team. She estimates that her chances of scoring on a penalty kick during a game are 75% when there is no wind, but only 60% on a windy day. If the weather forecast gives a 55% probability of windy weather today, what is the probability of Carrie scoring on a penalty kick in a math this afternoon?
p(score) = p(wind)p(score|wind) + p(nowind)p(score|nowind)

where p(a|b) means the probability of a given that p occurs.

RonL

3. Originally Posted by Desiderius
A four member curling team is randomly chosen from six grade 11 students and nine grade 12 students. What is the probability that the team has at least one grade 11 student?
p(n(11)>=1) = p(n(11)>0) = 1-p(n(11)=0)

So you need only find the probability of no grade 11 students in the team.

RonL