Example 1 Understanding and Planning The table shows the biking and running speeds (in meters per...
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Example 1 Understanding and Planning The table shows the biking and running speeds (in meters per minute) for both you and your friend. Who has the better total time? DUATHLON You and a friend decide to compete in a duathlon. You both bike 10,000 meters and run 4000 meters. To solve this problem, you need to make sure you understand the problem. Then make a plan for solving the problem.
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Transcript of Example 1 Understanding and Planning The table shows the biking and running speeds (in meters per...
Example 1 Understanding and Planning
The table shows the biking and running speeds (in meters per minute) for both you and your friend. Who has the better total time?
DUATHLON
You and a friend decide to compete in a duathlon. You both bike 10,000 meters and run 4000 meters.
To solve this problem, you need to make sure you understand the problem. Then make a plan for solving the problem.
Example 1 Understanding and Planning
READ AND UNDERSTAND
What do you know?
The table displays the speeds of you and your friend for biking and running.
You both bike 10,000 meters and run 4000 meters.
What do you want to find out?
Who has the better total time for biking and running?
Example 1 Understanding and Planning
MAKE A PLAN
How can you relate what you know to what you want to find out?
Find each of your biking and running times. You can organize this information in a table.
Find each of your total times and then compare these times.
You will solve the problem in Example 2.
Example 2 Solving and Looking Back
DUATHLON
Carry out the plan from Example 1 to solve the problem. Then, check your answer.
SOLVE THE PROBLEM
Use the formula Time .=Rate
Distance
Example 2 Solving and Looking Back
Biking Running
Friend
You=tr
d=
410
10,000
≈ 24.4 min
=tr
d=
430
10,000
≈ 23.3 min
=tr
d=
170
4000
≈ 23.5 min
=tr
d=
160
4000
≈ 25 min
Example 2 Solving and Looking Back
Add to find the total times.
47.9 min=23.5+24.4You
Friend 48.3 min=25+23.3
You have the better total time for the duathlon.
ANSWER
Example 2 Solving and Looking Back
LOOK BACK
Does your answer make sense?
You bike more slowly than your friend, so your biking time should be greater. You run faster than your friend, so your running time should be less. Therefore, the calculations are reasonable.
Guided Practice for Examples 1 and 2
1.
ANSWER 22.7 min; your friend
WHAT IF? In Examples 1 and 2, suppose that your friend bikes at a rate of 440 meters per minute. What is your friend’s biking time? Who has the better total time in the duathlon?
