Three <em>possible sets</em> are:
{11, 15, 28}; {3, 5, 28}; and {4, 7, 25}
Explanation:
"Relatively prime" means that the GCF is 1. Examining the sets above, 11 is only divisible by 1 and 11; 15 by 1, 3, 5 and 15; and 28 by 1, 2, 4, 7, 14, and 28. The GCF is 1.
For the second set, 3 is only divisible by 1 and 3; 5 is only divisible by 1 and 5; and 28 is divisible by 1, 2, 4, 7, 14 and 28. The GCF is 1.
For the third set, 4 is divisible by 1, 2 and 4; 7 is divisible by 1 and 7; and 25 is divisible by 1, 5 and 25. The GCF is 1.