Question

Runners in a 5k race were surveyed about their finishing times (f) and the number of previous races they had run (n). There was a negative linear relationship between f and n that is best modeled by the equation f=−1.2n+38.1 .

A The model predicts that the finishing time for a runner in a 5k race is about 38.1 minutes.B The model predicts that the finishing time for a runner who has run 1.2 previous 5k races is about 38.1 minutes.C The model predicts that for each additional race a runner has run, the finishing time decreases by about 1.2 minutes.D The model predicts that the finishing time for a runner in a 5k race is about 38.1 minutes.

Answer 1

The appropriate explanation of the model is C. the model predicts that for each additional race a runner has run, the finishing time decreases by about 1.2 minutes.
This is seen by the factor -1.2 being multiplied to the number of races, meaning there is a decrease of 1.2 per race. The base time taken, without having run any races, is 38.1 minutes.