1977 AHSME Problems/Problem 27

Problem

There are two spherical balls of different sizes lying in two corners of a rectangular room, each touching two walls and the floor. If there is a point on each ball which is $5$ inches from each wall which that ball touches and $10$ inches from the floor, then the sum of the diameters of the balls is

$\textbf{(A) }20\text{ inches}\qquad \textbf{(B) }30\text{ inches}\qquad \textbf{(C) }40\text{ inches}\qquad \textbf{(D) }60\text{ inches}\qquad \\ \textbf{(E) }\text{not determined by the given information}$