 Ashok works as a builder. In a typical week the probability he'll be working on a building site is 0.7. The probability he'll be working during the weekend is 0.2. Calculate the probability that Ashok will be working on the building site during the weekend. We need to read the question carefully, and delining or highlighting all of the important information. We need to remember the following probability rule. The probability of something happening plus the probability of something not happening is always equal to 1. Therefore the probability Ashok will not be working on the building site is 1 minus 0.7 which is equal to 0.3. Also the probability Ashok will not be working during the weekend is 1 minus 0.2 which is equal to 0.8. We also need to use the independent events rule to complete the second sets of branches for the working during the weekend. Working during the weekend is independent to working on a building site therefore the branches on the top and bottom are the same. We now need to multiply the probabilities of the independent events. The probability of Ashok working on the building site multiplied by the probability of Ashok working on the weekend. This is 0.7 multiplied by 0.2. This equals 0.14 which is the probability that Ashok will be working on the building site during the weekend.