 Hi, welcome to our session. Let us discuss the following question. The question says, from a bank containing 20 tickets, numbered from 1 to 20, two tickets are drawn at random. Find the probability that, first part is, both the tickets have prime numbers on them. Second part is, on one, there is a prime number, and on the other, there is a multiple of four. Now, we begin with the solution. But we have to find the probability that both the tickets have prime numbers on them. Now, prime numbers from 1 to probability that both the tickets have prime numbers on them, therefore, number of elements in a sample space that both the number on the tickets are from z equal to e2 divided by 20c2. CR is equal to n factorial divided by r factorial into n minus r factorial. Now, by using this, 8c2 is equal to 8 factorial divided by 2 factorial into 8 minus 2 factorial by divided by 2 factorial into 20 minus 2 factorial. This is equal to 6 factorial divided by 2 factorial into 8 factorial. This is equal to 6 factorial into 2 into 18 factorial by 20 factorial. 8 factorial can be written as, into 6 factorial, into we have 18 factorial divided by 6 factorial, into 20 factorial can be written as 20 into 19 into 18 factorial. Now, 6 factorial can be written as 18 factorial or 19 by 19. So, probability of drawing one ticket