1. STAAR REVIEW RATES & UNIT RATES

2. GETTING THE IDEA A rate is a comparison, or ratio, of two quantities with different units. For example, a store sells 3 T-shirts for $15. The comparison of $15 to 3 T-shirts is a rate. This rate can also be written as $15/3 T-shirts. When a rate compares a quantity to one unit of another quantity, the rate is a unit rate. The rate 15/3 T-shirts is not a unite rate because the rate compares the cost to more than one T-shirt. In a unit rate, the second quantity (or denominator) should be 1 unit. A speed limit is an example of a unit rate. For example, the speed limit of 55 miles per hour compares the distance to 1 hour. A speed of 55 miles per hour is equivalent to traveling 55 miles in each 1-hour time span. This can be written as Not a unit rateunit rate

3. EXAMPLE 1

4. STRATEGY Determine the ratios that have different units. A rate compares two quantities with different units. Different UnitsSame Units

5. EXAMPLE 2

6. EXAMPLE 3

7. EXAMPLE 4