The answer would be 7/24
You can start by finding a common denominator. Since the lowest common denominator 3 and 8 have in common is 24 then that would be your denominator.
Then you can cross multiply 3*3= 9 and 2*8=16

16-9= 7
7/24
Then you are left with your answer:
is already in reduced terms.
Hope this helps! :3