En una bolsa de 24 bolas, las bolas blancas son 1/4 de ellas. sin sacar ninguna,
¿cuantas bolas blancas debo añadir para conseguir que las blancas fuesen la mitad?

Afootball quarterback has two more chances to throw a touchdown before his team is forced to punt the ball. he misses the receiver on the first throw 25% of the time. when his first throw is incomplete, he misses the receiver on the second throw 15% of the time. what is the probability of not throwing the ball to a receiver on either throw?