BTGmoderatorLU wrote:Source: GMAT Prep

In 1995 a certain store had 1,800 tools in stock that had been purchased for $30 each. If 1,000 of these tools were sold in 1995 for $40 each and the remaining 800 were sold in 1996 for $50 each, how many greater was the gross profit on the tools sold in 1996 than the gross profit on those sold in 1995?

A. $0
B. $6,000
C. $8,000
D. $32,000
E. $40,000

\[\begin{array}{*{20}{c}}
{1800\,\,{\text{units}}} \\
{{\text{cost}}\,\,\$ 30\,{\text{each}}}
\end{array}\,\,\,\,\,\left\{ \begin{gathered}
\,\left( {95} \right)\,\,1000\,\,{\text{units}}\,,\,\,\,{\text{sold}}\,\,\$ 40\,\,{\text{each}}\,\,\,\,\, \to \,\,\,\,\,\,{\text{g}}{{\text{p}}_{\,95}}\,\, = \,\,\,\$ \,\,1000 \cdot \left( {40 - 30} \right) \hfill \\
\,\left( {96} \right)\,\,\,\,800\,\,{\text{units}},\,\,\,{\text{sold}}\,\,\$ 50\,\,{\text{each}}\,\,\,\,\, \to \,\,\,\,\,\,{\text{g}}{{\text{p}}_{\,96}}\,\, = \,\,\,\$ \,\,800 \cdot \left( {50 - 30} \right) \hfill \\
\end{gathered} \right.\]
\[? = {\text{g}}{{\text{p}}_{\,96}} - {\text{g}}{{\text{p}}_{\,95}} = 1000\left( {8 \cdot 2 - 10} \right) = 6000\,\,\,\,\left[ \$ \right]\]

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

Regards,
Fabio.