A number is selected from first 50 natural numbers. What is the probability that it is a multiple of 3 or 5?

Sure, here are the steps to solve this problem:

Step 1: Identify the total number of outcomes. In this case, a number is selected from the first 50 natural numbers. So, the total number of outcomes is 50.

Step 2: Identify the favorable outcomes. We need to find the numbers that are multiples of 3 or 5.

Multiples of 3 in the first 50 natural numbers are: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48. So, there are 16 multiples of 3.

Multiples of 5 in the first 50 natural numbers are: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50. So, there are 10 multiples of 5.

But, you can see that numbers 15, 30, and 45 are common in both sets because these are multiples of both 3 and 5. So, we should not count them twice.

Step 3: Calculate the total number of favorable outcomes. The total number of favorable outcomes is the number of multiples of 3 plus the number of multiples of 5, minus the numbers that are multiples of both 3 and 5. So, the total number of favorable outcomes is 16 + 10 - 3 = 23.

Step 4: Calculate the probability. The probability of an event is the number of favorable outcomes divided by the total number of outcomes. So, the probability that the selected number is a multiple of 3 or 5 is 23/50 = 0.46.