Okay so I’m not entirely understanding this question. So I guess I’ll give all possible answers.
If your question is 1/3 divided by 5
1/3 divided by 5/1 reciprocal and change the sign
1/3 • 1/5
1/15=a/20
Cross multiply. 15a=20
a=20/15
a=4/3
If your question is 1 divided by 3/5
1/1•5/3
5/3=a/20
100=3a
a=33.333333333 or 100/3
If your question is 1 divided by 3 divided by 5
1/1•1/3•1/5
1/15=a/20
20/15
a=4/3
Sorry if this was all confusing. Hopefully I helped even a little bit
