One member of the debate team is going to be chosen, President. Each member is equally likely to be chosen. The probability that a girl is chosen is 2/3 the probability that a boy is chosen. If the debate team has 20 people, how many girls are there?

rohitaop
May 31, 2018

#1**+2 **

The probability that a girl is chosen is 2/3 the probability that a boy is chosen.

This means that if there are x boys, there are a total of 2/3 x girls.

The total amount of kids in the class is 2/3x + 1x = 5/3x.

This is equal to 20.

\(\frac53x=20\Rightarrow{x}=12\)

Therefore, there are \(12\cdot\frac23=8\) girls.

We can verify this. The class has 20 people, 8 girls and 12 boys.

The probabilty a girl is chosen is 8/20 and boy is 12/20.

8/20 is also 2/3 of 12/20, so our answer is correct.

I hope this helped,

Gavin

GYanggg
Jun 1, 2018