[Solved] $\text { Prove for all integers } n , k \text {, and } r \text { with } n \geq k \geq r \text { that } \left( \begin{array} { l } n \\ k \end{array} \right) \left( \begin{array} { l } k \\ r \end{array} \right) = \left( \begin{array} { l } n \\ r \end{array} \right) \left( \begin{array} { l } n - r \\ k - r \end{array} \right) \text {. }$ Commercial Sexual Activity: Engaging in sexual acts in exchange for money or other valuable considerations. Sex Tourism: Travel undertaken with the motive of engaging in sexual activity, often commercial, in a destination where such activities are more accessible or permissible. Traveling: The act of moving from one place to another, which can be for various purposes such as exploration, leisure, or business. Queer Theory: An academic field that challenges the traditional, binary categorization of gender and sexuality, emphasizing the fluidity of sexual identity and questioning social norms.

Solved

question 4

Essay

$\text { Prove for all integers } n , k \text {, and } r \text { with } n \geq k \geq r \text { that } \left( \begin{array} { l } n \\k\end{array} \right) \left( \begin{array} { l } k \\r\end{array} \right) = \left( \begin{array} { l } n \\r\end{array} \right) \left( \begin{array} { l } n - r \\k - r\end{array} \right) \text {. }$

Definitions:

Commercial Sexual Activity

Engaging in sexual acts in exchange for money or other valuable considerations.

Sex Tourism

Travel undertaken with the motive of engaging in sexual activity, often commercial, in a destination where such activities are more accessible or permissible.

Traveling

The act of moving from one place to another, which can be for various purposes such as exploration, leisure, or business.

Queer Theory

An academic field that challenges the traditional, binary categorization of gender and sexuality, emphasizing the fluidity of sexual identity and questioning social norms.