Answer:
3/5
Explanation:
We want to find 3/4 of 4/5.
The keyword of tells us that we need to multiply. Therefore:

Multiply:

So, 3/4 of 4/5 is 3/5.
We can confirm this by converting them to decimals.
4/5 is 0.8.
3/4 is 0.75.
0.75 or 75% of 0.8 is indeed 3/5 or 0.6.