To find the equation that relates the number of miles \(y\) to the time in minutes \(x\) for the day you ran the fastest, we first need to determine the rate of running for each day.
On Monday, you ran 4 miles in 40 minutes:
\[ \text{Rate on Monday} = \frac{4 \text{ miles}}{40 \text{ minutes}} = 0.1 \text{ miles per minute} \]
On Wednesday, you ran 2 miles in 16 minutes:
\[ \text{Rate on Wednesday} = \frac{2 \text{ miles}}{16 \text{ minutes}} = 0.125 \text{ miles per minute} \]
Since you ran the fastest on Wednesday, the equation that relates \(y\) and \(x\) for that day is:
\[ y = 0.125x \]
So the correct response is:
y=0.125x