 Hello and welcome to the session. I am Deepika here. Let's discuss the question which says A box contains 12 balls out of each X of black. If one ball is drawn at random from the box What is the probability that it will be a black ball? If six more black balls are put in the box The probability of drawing a black ball is now double of what it was before. Find X Now we know that the probability of an event E written as P E is equal to number of outcomes favorable to E upon number of all possible outcomes of the experiment. So this is the key idea behind our question We will take the help of this key idea to solve the above questions. Let's start the solution According to the question a box contains 12 balls and one ball is drawn at random from the box. Therefore there are 12 equally likely outcomes. So the number of possible outcomes is equal to 12. Now out of 12 balls Therefore the number to black ball is equal to X which is equal to probability of getting a black ball. So this is equal to number of outcomes favorable to black ball putting the box. The total number of balls in the box is equal to 12 plus 6 which is equal to 18. The number of black balls in the box is equal to what is the probability of getting a black ball now. So P2 is equal to because now there are 18 balls in the box and out of 18 balls X plus 6 are black. It is written X upon 18 is equal to equal to X upon 6 into 18 plus X plus 6 is equal to and this implies 3 X minus X is equal to 6. This implies 2 X is equal to 6 X is equal to. So further above question is the probability of a black ball is X upon 12 is equal to the solution is clear to you. Bye and take care.