What is the minimum number of times a fair coin must be tossed so that the probability of getting at least one head exceeds 0.95?

There is a 4-in-5 chance that A can complete the marathon. There is a 5-in-8 chance that B can't complete the marathon, which is independent of A's performance. What is the probability that both A and B end up completing?

A three-digit number is chosen at random. Find the probability that its hundreds digit, tens digit and units digit are consecutive integers in descending order

When three coins are tossed simultaneously, what is the probability of getting exactly one tail?

Two dice were rolled simultaneously. Find the probability that the sum of the numbers on them was a prime number.