Okay so turn those into improper fractions first, so 4/1 divided by 20/3. Then use the KCF method and keep, change flip. You keep 4/1, change division to multiplication, then flip 20/3 to 3/20. You should have
4/1 • 3/20. Then multiply straight across. So, you’ll have 12/20. Then simplify to 3/5 using common factors.
Thus, your simplified answer is 3/5.