Answer: 15
Explanation:
Sorting the numbers from least to greatest, we get the order 5, 10, 12, 15, 21, 31, 50, 68, 70, 80, 83, 84, 90, 93, 100.
The median is 68.
The first quartile is the median of the first half of the integers (from 1-7), thus the first quartile is 15.