A Poll of 120 Ithacans Found That 30 Had Visited

Multiple Choice

A poll of 120 Ithacans found that 30 had visited the Museum of the Earth, and that 80 had been to Home Depot. If it appeared that going to Home Depot and going to the Museum of the Earth were independent events, how many of those polled had been to both? $\begin{array}{lr|c|c|c} & &{\text { Museum }} & \\& & \text { Yes } & \text { No } & \text { Total } \\\hline \text { Home } & \text { Yes } & ? ? & & 80 \\\hline \text { Depot } & \text { No } & & & 40 \\\hline & \text { Total } & 30 & 90 & 120\end{array}$

A) 24
B) 20
C) 10
D) It cannot be determined.
E) 15