Could you explain in a detail why those answers are 50% and 0.42?

70% of your friends like Chocolate, and 35% like Chocolate AND like Strawberry. What

percent of those who like Chocolate also like Strawberry?

A)50%

You are off to soccer, and want to be the Goalkeeper, but that depends who is the

Coach today:

with Coach Sam the probability of being Goalkeeper is 0.5

with Coach Alex the probability of being Goalkeeper is 0.3

Sam is Coach more often ... about 6 out of every 10 games (a probability of 0.6).

So, what is the probability you will be a Goalkeeper today?

A)0.42