Pg 519 (451) - Q11
The factors of 15 that are integers greater than 1 are 3 and 5, and
the factors of 33 that are integers greater than 1 are 3 and 11.
Since s has to be a factor of both 15 and 33, and the only factor that
is an integer greater than 1 both 15 and 33 have in common
is 3, s must be 3. This makes r = 5 and t = 11. And
since 11 > 5 > 3, t > r > s, or A.