Respuesta :
Solution:
Given that there are approximately 2 lb of muscle for every 5 lb of body weight, this implies that
[tex]2\text{ lb muscle}\Rightarrow5\text{ lb body weight}[/tex]Let y represent the muscle of a 90 lb person. This implies that
[tex]y\text{ lb muscle}\Rightarrow90\text{ lb body weight}[/tex]Thus, to evaluate the value of y,
[tex]\begin{gathered} 2\text{ lb muscle}\Rightarrow5\text{ lb body weight} \\ y\text{ lb muscle}\Rightarrow90\text{ lb weight} \\ cross-multiply, \\ 2\text{ lb muscle}\times90\text{ lb weight = y lb muscle}\times5\text{ lb body weight} \\ divide\text{ both sides by 5 lb body weight} \\ \frac{2\text{ }lb\text{ }muscle\times90\text{ }lb\text{ }weight}{5\text{ lb body weight}}\text{ = }\frac{y\text{ }lb\text{ }muscle\times5\text{ }lb\text{ }body\text{ }weight}{5\text{ lb body weight}} \\ y=2\text{ lb muscle}\times\frac{90}{5} \\ \Rightarrow y=\text{ 36 lb muscle} \end{gathered}[/tex]Hence, for a 90-lb person, the approximate lb of muscle is
[tex]36\text{ lb muscle}[/tex]