Lesson 7-1 Converting Units
Key Concept:
• Constant Speed- Constant speed is a rate comparing distance to time. If the car travels 10
!"#$%
miles in 1 hour, the car’s speed is the rate 10 !!"#
• Time- The total distance the car travels depends on the total amount of time. The speed of the
car is given in miles per hour, so the number line shows the time in hours.
• Distance- For each hour the car travels, the total distance increases by 10 miles
• Using d=rt- you can use the equation d=rt to find a distance rate, or time.
Part One: Finding Distance
Example:
Notice Speed (r) is 45 minutes per hour but time (t) is in minutes…
Step One: Make minutes into hours.
Step Two: Use the equation d=rt to find the distance traveled.
Your Turn:
Lisa bikes at a constant speed of 8 miles per hour. If she bikes for 30 minutes, how far does she
travel?
Part Two: Finding Speed
Example:
Use the equation d=rt
Substitute what you know, d & t, and then solve for “r”
Your Turn: A bus travels 70 miles in 2 hours. What is the speed of the bus in miles
per hour? Use the equation d=rt
Part Three:
Example: On a busy road, cars can travel only 5 miles in 10 minutes. At this speed,
how far will a car travel in 15 minutes?
Your Turn: On an even busier day, your friends’ mother drives 12 miles in 36
minutes. At this speed, how long does it take your friends mother to drive 2 miles?
Your Turn 2: Your friend plans to bike to school. Your friend bikes at a constant
speed of 9 miles per hour and lives 6 miles from school. If your friend leaves home 35
minutes before school starts, will your friend make it to school on time?
Part Four: Finding a Rate with a Table
Example: Participants in a charity walk-a-thon log how far they have walked at the
end of each hour. They walk at a constant speed. Fill out the third column in the table to
find this rate.
Your Turn: Participants in a charity bike-a-thon log how far they have biked at the
end of each hour. They bike at a constant speed. Fill out the third column in the table to
find this rate.