A lap around the track is equal to one-fourth of a mile. A runner runs 5 laps in 12 minutes and 30 seconds. What was the runner's average speed in miles per hour?
Do not include units (miles per hour) in your answer.
Type your answer below as a number (example: 5, 3.1, 41/2, or 3/2):

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.