A child is throwing darts at the board shown in the figure. The radii of the circles on the board are 3 cm, 6 cm and 9 cm respectively. What is the probability that the child's dart lands in the red circle, given that it hits the board?

An urn contains 3 black, 4 red and 2 blue marbles. What is the probability that a marble drawn at random is not blue?

A box contains 15 light bulbs, 4 of which are defective. Abulb i sselected at random. What is the probability that it is not defective?

A number is drawn at random from the set A= {1, 2, 3, ... ,100}. What is the probability that the number is divisible by both 2 and 3?

The integers 1 through 15 are written on separate cards. You are asked to pick a card at random. What is the probability that you pick a prime number?

Two dice are rolled. What is the probability that their sum is divisible by 4?

An urn contains five blue marbles, four red marbles and sxi yelow marbles. We want ot take one marble from the urn. What is the probability of taking a red or a yellow marble?

Two dice are rolled together. What is the probability of obtaining a sum less than 6?

Three dice are rolled together. What is the probability of rolling a sum of 15?

Two dice are rolled. What is the probability that their sum is a prime number?

A coin is tossed four times. What is the probability that the coin shows tails at least once?