19
% decrease = |original value - new value|/original value * 100% = |81 - 91|/81 * 100% = 10/81 * 100% = 0.1234 * 100% = 12.34%
That's an infinite list. 81, 83, 85, 87, 89, 91 and so on.
80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100
number of composite numbers between 81 and 100 = 15composite numbers between 81 and 100 = 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99
80, 81, 82, 84, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100.
80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100
The numbers 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99 and 100 are composite (including the boundaries).
It is 91 times 87 = 7,917
91
The median is the average of 85 and 87, that is 86.The median is the average of 85 and 87, that is 86.The median is the average of 85 and 87, that is 86.The median is the average of 85 and 87, that is 86.
The median of those numbers is 90.