Probability = the number of ways of achieving success. The total number of possible outcomes. For example, the probability of flipping a coin and it being heads is ½, because there is one way of getting a head and the total number of possible outcomes is 2 (a head or tail). We write P (heads) = ½. There is always a degree of certainty or uncertainty about what has happened or going to happen. It leads to finding the probability of an occurrence of an event. Chapter – 13 Probability contains two exercises. Probability today has become one of the basic tools of statistics and has a wide range of applications in Science and Engineering. The problems are about games of chances such as throwing dice, tossing a coin, drawing a card from a pack of cards etc.