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?
+36916 b+g =20 or b = 20-g
and g = 2/3b sub in the definition of b above
g = 2/3 (20-g)
g = 40/3 - 2/3 g
5/3 g = 40/3
5 g = 40
g = 8
