2005 Cayley Problem 20

There are 81 cars in the CMC parking lot, which are all Acuras, Beetles, or Camrys. There are half as many Acuras as Beetles. The number of Camrys is 80\% of the number of Acuras and Beetles together. How many of the 81 cars are Beetles?

\textbf{(A)}\ 36\quad \textbf{(B)}\ 30\quad \textbf{(C)}\ 45\quad \textbf{(D)}\ 51\quad \textbf{(E)}\ 66

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.