Probability-Independent events

Question 1

Probability of H

Answer 1

1/2

Question 2

Probability of 1st H, 2nd H, 3rd H

Answer 2

1/8

Question 3

The probability that Bob eats a burger today is 0.3. The probability that his wife Babette eats a burger today is 0.6. The probability that they both eat a burger is 0.2. Are the events of Bob and Babette eating burgers independent?

Answer 3

They are not because if they were the answer would be 0.18 but instead its 0.2

Question 4

Bart and Bertie go to see a movie. The probability that Bart enjoys the movie is 0.6. The probability that Bertie enjoys the movie is 0.3. These two events are independent.

a) whats the probability they both enjoy the movie?
b) whats the probability that exactly one of them enjoys the movie?

Answer 4

a) 0.6 times 0.3 = 0.18

b) 0.54

Question 5

Here are seven tiles:
1 1 2 2 2 3 3
Jim takes a random tile- he doesn’t replace it. Jim then takes at random a second tile.
a) calculate the probability that both the tiles Jim takes have the number one on them?

Answer 5

2/7 times 1/6= 2/42