 Hi and welcome to the session. Let us discuss the following question. Question says, a box contains five red marbles, eight white marbles and four green marbles. One marble is taken out of the box at random. What is the probability that marble taken out will be red, white, not green? First of all, let us understand that probability of occurrence of an event E denoted by P e is equal to number of outcomes favourable to E upon total number of possible outcomes. Also probability of E plus probability of not E is equal to 1. Here E bar represents not E, E and E bar are two complementary events. Clearly we can see some of probabilities of two complementary events is equal to 1. So we will use these two expressions as our key idea to solve the given question. Let us now start with the solution. Now we are given that there are five red marbles, eight white marbles and four green marbles in a box. So total number of marbles in the box is equal to 17. So we can write total number of marbles in the box is equal to 5 plus 8 plus 4 which is further equal to 17. Now out of these 17 marbles, one can be chosen in 17 ways. So total number of outcomes is equal to 17. Now we have to find probability of red marbles. We know box contains five red marbles. Clearly we can see these are five red marbles and each of the marbles can be drawn in five ways. So total number of favourable outcomes is equal to 5. So we can write number of favourable outcomes red marble is equal to 5. So probability of red marble is equal to 5 upon 17. From key idea we know probability of E is equal to number of outcomes favourable to E upon total number of possible outcomes. So here probability of getting red marble is equal to number of outcomes favourable to red marble upon total number of possible outcomes. Now this completes the first part of the given question. Let us now start with the second part. Now we have to find probability of getting white marble. Now we know there are eight white marbles in the box. Therefore one white marble can be drawn in eight ways. So we can write number of favourable outcomes to white marble is equal to 8. We know probability of white marble is equal to number of favourable outcomes to white marble upon total number of possible outcomes. Now we get probability of white marble is equal to 8 upon 17. We know number of favourable outcomes to white marble is equal to 8 and total number of possible outcomes is equal to 17. So probability of getting white marbles is equal to 8 upon 17. Now let us start with the third part of the given question. We have to find probability of not green marble. Clearly we can see number of marbles which are not green are five red marbles and eight white marbles. And we know five plus eight is equal to 13. So there are 13 marbles which are not green. Now clearly we can see one marble out of these 13 marbles which are not green can be drawn in 13 ways. So number of favourable outcomes to not green is equal to 13. Now we know probability of not green marble is equal to number of favourable outcomes to not green upon total number of possible outcomes. We know number of favourable outcomes to not green is equal to 13 and total number of possible outcomes is equal to 17. So we get probability of getting not green marble is equal to 13 upon 17. Or we can say probability of not getting green marble is equal to 13 upon 17. Now this completes the third part of the given question. Now these are the required answers for the three parts given in the question. This completes the session. Hope you understood the solution. Take care and keep smiling.