30
17,19,23,29
It is 30-15 = 15
15 percent of 30 = 4.515% of 30= 15% * 30= 0.15 * 30= 4.4
, 21, 22, 24, 25, 26, 27, 28
30
23
17,19,23,29
15
14 and 21, and 21 and 28 are the number pairs between 15 and 30 that have 7 as their greatest common factor.
It is 30-15 = 15
15 is 30% of 50
15 percent of 30 = 4.515% of 30= 15% * 30= 0.15 * 30= 4.4
10, 15, 20, 25 and 30
(10+20)/2 = 30/2 = 15
, 21, 22, 24, 25, 26, 27, 28
There cannot be any number between two identical numbers.