X ~ Binomial(n = 3, p = 0.7) (assuming the 3 people are chosen from a 'large' group).
You should know what to do from here.
2. Let Y be the random variable number of people who rated the movie awful.
Technically the exact probability is .
An approximate solution would consider Y ~ Binomial(n = 3, p = 1/10) (since 100 is large).
Then calculate .
I doubt you'll find a lot of difference between the two answers in the first two or so decimal places.