A building is to be built on a lot that measures 80 m by 60 m. A lawn of uniform width, equal to the area of the building, must surround it. How wide is the strip of lawn.

Question

$\begin{array}{1 1} (a)\; 10\;m \\ (b)\; 15\;m \\ (c)\; 18\;m \\ (d)\; 20\;m \end{array}$