Answer:
Therefore, the probability of getting at least 3 tails is 1/16 + 1/4 = 5/16 or 0.3125.
The probability of getting exactly 3 tails is just 1/4, as we calculated above.
Explanation:
To find the probability of getting at least 3 tails when tossing a coin 4 times, we need to add the probabilities of getting 3 tails and 4 tails.
The probability of getting a tail on one toss is 1/2, and the probability of getting a head is also 1/2.
The probability of getting 4 tails is (1/2)^4 = 1/16 because there is a 1/2 chance of getting a tail on each toss, and the events are independent, so we multiply the probabilities together.
The probability of getting 3 tails is (4 choose 3) * (1/2)^4 = 4/16 = 1/4 because we need to choose which 3 tosses will be tails (this can be done in (4 choose 3) = 4 ways), and there is a 1/2 chance of each of those tosses being a tail, with a 1/2 chance of the last toss being a head.