To find out what "?" represents in the equation "? fifths = 20", you can set up the equation as follows:
\[ ? \times \frac{1}{5} = 20 \]
Multiplying both sides by 5 to isolate "?", you get:
\[ ? = 20 \times 5 \]
Calculating the right side:
\[ ? = 100 \]
So, the answer is 100. Therefore, 100 fifths equal 20.