Question

2.There are approximately 2 lb muscle for every 5 lb of body weight. For a 90-lb person, approximately how much of that weight is muscle?

Answer 1

Given that there are approximately 2 lb of muscle for every 5 lb of body weight, this implies that

`2\text{ lb muscle}\Rightarrow5\text{ lb body weight}`

Let y represent the muscle of a 90 lb person. This implies that

`y\text{ lb muscle}\Rightarrow90\text{ lb body weight}`

Thus, to evaluate the value of y,

`\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}*90\text{ lb weight = y lb muscle}*5\text{ lb body weight} \\ divide\text{ both sides by 5 lb body weight} \\ \frac{2\text{ }lb\text{ }muscle*90\text{ }lb\text{ }weight}{5\text{ lb body weight}}\text{ = }\frac{y\text{ }lb\text{ }muscle*5\text{ }lb\text{ }body\text{ }weight}{5\text{ lb body weight}} \\ y=2\text{ lb muscle}*(90)/(5) \\ \Rightarrow y=\text{ 36 lb muscle} \end{gathered}`

Hence, for a 90-lb person, the approximate lb of muscle is

`36\text{ lb muscle}`