A fair six sided die is rolled twice. What is the theoretical probability that the first number comes up is greater than or equal to the second number

Answer: 7/12

Step-by-step explanation:

There are 6 * 6 = 36 ways to roll two dice, 6 of them gives two of the same number. Of the remaining, there will be 36-6 = 30 ways, and the number of rolls where the first dice is greater than the second dice should be the same as the number of rolls whereby the second dice will be greater than the first. Therefore, there will be 30/2 = 15 ways whereby the first roll will be greater than the second roll.

The probability the first number will be greater than or equal to the second number is:

(15 + 6) / 36 = 21/36 = 7/12