Mr. Menendez ran 13.1 miles at a constant rate for 150 minutes. To find how fast he ran, you solve the equation 13.1 = x • 150. What does x represent?

1.) His speed in miles per minute

2.) The total distance after x minutes

3.) The number of miles he has run so far

4.) The amount of time it takes to run 13.1 miles

X represents his unit rate which is answer #1, speed in miles per minute. It wouldn't make sense to have total distance which is #2 because his total distance is what you are using to find out what x is! Then the number of miles he has run so far makes no sense whatsoever so eliminate that, then 4 is basically is the time it takes to run 13.1 miles which is 150. Hope you understand why the answer is 1. and mark as brainliest!