Answer: Around 135 days
Step-by-step explanation:
The number is randomly chosen, and we have numbers from 1 to 20, so each number has a 1/20 probability of being chosen.
The numbers that are greater than 5, are the numbers from 6 to 20, so we have 15 options that are greater than 5.
Then the probability of choosing a number that is greater than 5 (for each day) is equal to 15/20.
p = 15/20 = 0.75
So we expect that in a 0.75 of the 180 days a number bigger than 5 is chosen, this is:
0.75*180 = 135 days
