Remember, a ratio is a comparison between two quantities. Ratios can compare a part to a whole, like comparing the number of girls in your classroom to the total number of students in your classroom. Ratios can also compare a part to a part, like comparing the number of peppers on your pizza to the number of olives on your pizza. A rate is a special kind of ratio that compares quantities, or amounts, with different units. This means the two quantities in a rate measure different things. One of the quantities often measures something like time, distance or money. A rate shows how much of something is happening per unit of another thing. For example, one rate you see very often is miles per hour. That rate tells you how many miles you’re going for every hour you travel. If you’re driving 35 miles per hour, you travel 35 miles every hour. Which of the following can be written as a rate?