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IB Mathematical Studies SL – Probability, Conditional Probability

Can anyone help me with the following probability exercise?

“In a class of 27 students, 7 play football (F) and 18 play basketball (B). Three students play neither. ” One student is randomly selected from the class. What is the probability that the student plays football given that also plays basketball??”

Thanks

Can anyone help me with the following probability exercise?

“In a class of 27 students, 7 play football (F) and 18 play basketball (B). Three students play neither. ” One student is randomly selected from the class. What is the probability that the student plays football given that also plays basketball??”

Thanks

- hill
**Posts:**0**Joined:**Tue Mar 19, 2013 8:49 pm

IB Mathematical Studies SL – Probability, Conditional Probability

If you draw a Venn diagram and set x the number of students that play only football, y the number of students that play both, z the number of students that play only basketball then you will have the following equations

(1)

From the equation which are the students that play football, we have from (1) that

From the equation which are the students that play basketball, we have from (1) that is the number of students that play both.

So, the required conditional probability is given by the following formula:

Hope these help!!

If you draw a Venn diagram and set x the number of students that play only football, y the number of students that play both, z the number of students that play only basketball then you will have the following equations

(1)

From the equation which are the students that play football, we have from (1) that

From the equation which are the students that play basketball, we have from (1) that is the number of students that play both.

So, the required conditional probability is given by the following formula:

Hope these help!!

- elizabeth
**Posts:**0**Joined:**Mon Jan 28, 2013 8:09 pm

Thanks Elisabeth!!

- hill
**Posts:**0**Joined:**Tue Mar 19, 2013 8:49 pm

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