2023 Cayley Problem 8

Charlie is making a necklace with yellow beads and green beads. She has already used 4 green beads and 0 yellow beads. How many yellow beads will she have to add so that \frac{4}{5} of the total number of beads are yellow?

\textbf{(A)}\ 16\quad \textbf{(B)}\ 4\quad \textbf{(C)}\ 20\quad \textbf{(D)}\ 24\quad \textbf{(E)}\ 12

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Cayley contests here.