Question

The body mass index (BMI) of an adult is directly proportional to the person's weight, in pounds. If acertain adult weighing 145 pounds has a BMI of 23.2, what would be the new BMI of the person afterlosing 5 pounds?

Answer 1

If the BMI is directly proportional to the person's weight (in pounds), then:I

`BMI=k\cdot w`

Where w is the weight and k is a constant of proportionality. We know that if w = 145 pounds, the BMI is 23.2. Then:

`\begin{gathered} 23.2=k\cdot145 \\ \\ \Rightarrow k=0.16 \end{gathered}`

Finally, if the person loses 5 pounds, w = 140 pounds. Using the first equation:

`\begin{gathered} BMI=0.16\cdot140 \\ \\ \therefore BMI=22.4 \end{gathered}`