Answer :

                 
5 / 6 or 1 1/5

ask your teacher if she or he want improper fractions (like 6/5) or mixed numbers (like 1 1/5). I think the improper fraction is the simplified form, but some teachers disagree.
if u are not home schooled
hi well the answer is 5/6. i did that by because you just do this 15 goes into 5 and 18 goes into 6 so 5/6