Probability - General Questions

A number is chosen at random from 1 to 50. What is the probability that it is a multiple of 7?

4 unbiased coins are tossed together. What is the probability of getting at least one head?

Two dice are thrown together. What is the probability that the sum of the numbers is 9?

A bag contains 3 red, 5 blue and 2 green balls. Two balls are drawn at random. What is the probability that both are red?

Two dice are thrown together. What is the probability that the sum of the numbers is 12?