Precalculus (6th Edition) Blitzer

The required value is $k=8$
The provided equation is, $S=\frac{kA}{P}$ Put the values of A, P and S in the formulae. \begin{align} & 12000=\frac{k\times 60000}{40} \\ & k=\frac{12000\times 40}{60000} \\ & k=8 \end{align} Therefore, the value of $k=8$.