Bunuel wrote:

Eleven members of Club A are also members of Club B, and five members of Club B are also members of Club C. How many members of Club A are also members of Club C?

(1) Club B has 16 members.

(2) Exactly two people from Club C are also members of Club A.

We consider the image attached.

\(? = x + y\)

\(\left. \begin{gathered}

y + z = 11 \hfill \\

y + w = 5 \hfill \\

\end{gathered} \right\}\,\,\,\,\left( * \right)\)

\(\left( 1 \right)\,\,\underline {B = 16} \,\,\,\left\{ \begin{gathered}

\,\,{\text{Take}}\,\,\left( {x,\underline {y,z,w,k} } \right) = \,\,\left( {0,\underline {4,6,1,5} } \right)\,\,\,{\text{viable}}\,\,\,\,\, \Rightarrow \,\,\,\,? = 0 + 4 = 4 \hfill \\

\,\,{\text{Take}}\,\,\left( {x,\underline {y,z,w,k} } \right) = \,\,\left( {1,\underline {4,6,1,5} } \right)\,\,\,{\text{viable}}\,\,\,\,\, \Rightarrow \,\,\,\,? = 1 + 4 = 5 \hfill \\

\end{gathered} \right.\)

\(\left( 2 \right)\,\,x + y = 2\,\,\,\, \Rightarrow \,\,\,\,? = 2\,\,\,\,\left( {{\text{immediately}}} \right)\,\,\,\,\)

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

Regards,

fskilnik.

Attachments

06Set18_11y.gif [ 26.15 KiB | Viewed 387 times ]

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Fabio Skilnik :: https://GMATH.net (Math for the GMAT) or GMATH.com.br (Portuguese version)

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