An anti-aircraft gun can fire four shots at a time. If the probabilities of the first, second, third and the last shot hitting the enemy aircraft are 0.7, 0.6, 0.5 and 0.4, what is the probability that four shots aimed at an enemy aircraft will bring the aircraft down?
Two squares are chosen at random on a chessboard. What is the probability that they have a side in common?
What is the probability that a two digit number selected at random will be a multiple of '3' and not a multiple of '5'?