Question

Every day, Navya's teacher randomly picks a number from 1 to 80 to be the number of the day. The number of the day can be repeated. There are 180 days in the school year. Predict how many days the number of the day will be greater than 20.

Answer 1

Out of all the numbers from 1 to 80, there are (80-20)/(80) = 60/80 = 0.75
of them that are greater than 20 .

So every time you pick one at random, there a 75% chance that it will be
greater than 20.

If everything works out according to pefectly random probabilities, then
in 180 selections, 75% of them = (0.75 x 180) = 135 of the selections
would be numbers greater than 20 .