Hi there!
Unit rates are basically changes expressed as a quantity of one. For example, if we have something like 100 feet per second or 2 meters per hour, those are unit rates. In this case, we have a multiple-unit rate - 3 1/2 miles in 1 1/4 hours. First off, we need to simplify both fractions to an improper fraction, giving us 7/2 miles and 5/4 hours. Now, we need to divide 7/2 by 5/4.
7/2 ÷ 5/4
Find the reciprocal of 5/4:
7/2 × 4/5
Multiply:
28/10 → 2.8
Therefore, Jungkook walks 2.8 miles in one hour, or 2.8 mi/hour. Hope this helped!