AAPL wrote:Magoosh
In Dives Corporation, 75% of the employees are customer service representatives, 15% are programmers, and 10% are managers. The customer service representatives have an average salary of $60,000, and the programmers have an average salary of $100,000. If the average salary of all employees is also $100,000, what is the average salary of the managers?
A. $140,000
B. $180,000
C. $260,000
D. $400,000
E. $560,000
All numbers related to salaries will be presented in
thousands (of dollars).
(*) Homogeneity nature of the average
\[{\text{(say)}}\,\,100\,\,{\text{employees}}\,\,\,\left\{ \begin{gathered}
\,75\,\,{\text{representatives}}\,\,\,\, \to \,\,\,\,\$ {\text{60}}\,\,\,{\text{each}}\,\,{\text{ }}\,\,\left( * \right) \hfill \\
\,15\,\,{\text{programmers}}\,\,\,\, \to \,\,\,\,\$ {\text{100}}\,\,\,{\text{each}}\,\,\,\,\left( * \right) \hfill \\
\,10\,\,{\text{managers}}\,\,\,\, \to \,\,\,\,\$ \,{\text{x}}\,\,\,{\text{each}}\,\,\,\,\left( * \right) \hfill \\
\end{gathered} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\]
\[? = x\]
\[\left( * \right)\,\,\,\, \Rightarrow \,\,\,\,\left\{ \begin{gathered}
\,\,\sum\nolimits_{75} = \,\,\,75 \cdot \$ 60\,\, \hfill \\
\,\,\sum\nolimits_{15} = \,\,\,15 \cdot \$ 100 \hfill \\
\,\,\sum\nolimits_{10} = \,\,\,10 \cdot \$ x \hfill \\
\,\,\sum\nolimits_{100} = \,\,\,100 \cdot \$ 100\,\,\,\,\,\,\,\left( {\$ 100\,\,{\text{average}}\,\,{\text{in}}\,\,{\text{total}}} \right) \hfill \\
\end{gathered} \right.\]
\[75 \cdot 60 + 15 \cdot 100 + 10x = 10000\,\,\,\,\,\, \Rightarrow \,\,\,\,\,? = x = \frac{{10\left( {1000 - 3 \cdot 150 - 150} \right)}}{{10}} = \underleftrightarrow {1000 - 4 \cdot 150} = 400\,\,\,\,\left[ {{{10}^3}\,\,{\text{dollars}}} \right]\]
This solution follows the notations and rationale taught in the GMATH method.
Regards,
Fabio.