Question

19.When Jessica plavs basketball, the number of calories she burns is proportionalto the number of minutes she plays. She burns 261 calories for every30 minutes she plays and burns 348 calories for every 40 minutes she plays.What is the constant of proportionality?

Answer 1

Let y be the number of calories and x the number of minutes; therefore, according to the question, the two given ratios are

$\begin{gathered} \frac{y}{x}=\frac{261}{30}=\frac{348}{40} \\ \Rightarrow\frac{y}{x}=8.7=8.7 \\ \Rightarrow y=8.7x \end{gathered}$

Therefore, the constant of proportionality is 8.7, 8.7 calories per minute.