BTGmoderatorLU wrote:Source: GMAT Paper Tests

A company sells two products, L and M. Last year, seventy percent of the units sold were product L, and the price of product L was 25 percent greater than the price of product M. Approximately what percent of the total revenue the company received last year was from the sale of product L?

A. 15%
B. 25%
C. 35%
D. 65%
E. 74%

Let´s explore a "double particular case", choosing a suitable number of (total) units and a suitable unitary price (for product M)!
\[10\,\,{\text{units}}\,\,\,\left\{ \begin{gathered}
\,7\,\,{\text{units}}\,\,L\,\,\,\, \to \,\,\,\$ 5\,\,{\text{each}} \hfill \\
\,3\,\,{\text{units}}\,\,M\,\,\,\, \to \,\,\,\$ 4\,\,{\text{each}} \hfill \\
\end{gathered} \right.\]
\[? = \frac{{7 \cdot 5}}{{7 \cdot 5 + 3 \cdot 4}} = \frac{{35}}{{47}} = \underleftrightarrow {\frac{{35 \cdot 2}}{{47 \cdot 2}} = \frac{{70}}{{94}}} > 70\% \,\,\, \Rightarrow \,\,\,\left( E \right)\]

This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.