2015 Pascal Problem 22

The chart shown gives the cost of installing carpet in four rectangular rooms of various sizes. The cost per square metre of installing carpet is always the same.

\text{Width (metres)} \text{Length (metres)}\ \begin{array}{c||c|c}\hline & 10 & y \\ \hline 15 & \$397.50 & \$675.75 \\ \hline x & \$742.00 & \$z \\ \hline\end{array}

What is the value of z?

\textbf{(A)}\ 331.25\quad \textbf{(B)}\ 463.75\quad \textbf{(C)}\ 1815.25\quad \textbf{(D)}\ 476.00\quad \textbf{(E)}\ 1261.40

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 Pascal contests here.