1. EXAMPLE 1 Use a formula High-speed Train The Acela train travels between Boston and Washington, a distance of 457 miles. The trip takes 6.5 hours. What is the average speed? SOLUTION You can use the formula for distance traveled as a verbal model. 457 = r 6.5 Distance (miles) = Rate (miles/hour) Time (hours)

2. EXAMPLE 1 Use a formula An equation for this situation is 457 = 6.5r. Solve for r. 457 = 6.5r 70.3r Write equation. Divide each side by 6.5. The average speed of the train is about 70.3 miles per hour. ANSWER You can use unit analysis to check your answer. 457 miles 6.5 hours 70.3 miles 1 hour CHECK

3. GUIDED PRACTICE for Example 1 1. SOLUTION AVIATION: A jet flies at an average speed of 540 miles per hour. How long will it take to fly from New York to Tokyo, a distance of 6760 miles? You can use the formula for distance traveled as a verbal model. 6760 = 540 t Distance (miles) = Rate (miles/hour) Time (hours)

4. GUIDED PRACTICE for Example 1 An equation for this situation is 6760 = 540t. Solve for t. 6760 = 540t 12.5t Write equation. Divide each side by 540. Jet takes about 12.5 hours to fly from New York to Tokyo. ANSWER