4.
There are 12 numbers in the sample.
Out of those 12 numbers 5 are less than 100, which means 5 out of 12 people would have birthdays in the first 100 days.
Divide the number of people who would have birthdays in the first 100 days by the sample size:
5 / 12 = 0.417
5.
Out of the 15 numbers given 5 are between 7.0 and 8.0
The probability would be 5/15 = 0.333