tool bag formulas, equations, vocabulary, etc. here’s how…notes & examples title: name date...
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Tool BagFormulas, equations,Vocabulary, etc.
Here’s How…Notes & Examples
Title: Name Date Period
5-2 (Part 3): Rates Using Bar Models
Objective To use bar models to determine rates.Example #1
A car leaves Oakland for Las Vegas traveling an average of 40 mph. Two hours later, a truck leaves the same place in Oakland for Las Vegas at 60 mph. How long will it be beforethe truck overtakes the car?
Bar Model Method
401
402
403
404
The time it takes the truck to overtake the car is 4 hours....
Overtake/Catch-Up Problem
405
4060
Hours
Distance80 120 160 200 2400 40
Car:
00
00
601
602
603
6040
Hours
Distance0 60 120 180 2400 0
Truck:
Tool BagFormulas, equations,Vocabulary, etc.
Here’s How…Notes & Examples
Title: Name Date Period
5-2 (Part 3): Rates Using Bar Models
Equation Method40(x+2) = 60x
The time it takes the truck to overtake the car is 4 hours....
40x + 80 = 60x40x – 40x + 80 = 60x – 40x
80 = 20x
You Try A sailboat leaves San Francisco for Los Angeles at 30 mph. A motorboat leaves the same place two hours later in San Francisco for Los Angeles at 50 mph. How long will it take until the motorboat catches up to the sailboat?
Let x = the time it takes the truck to overtake the car.
8020
20x20
=
4 = x
Tool BagFormulas, equations,Vocabulary, etc.
Here’s How…Notes & Examples
Title: Name Date Period
5-2 (Part 3): Rates Using Bar Models
Example #2
A car leaves San Francisco for Anaheim traveling an average of 65 mph. At the same time, another car leaves Anaheim for San Francisco traveling an average of 60 mph. If it is 500 miles between San Francisco and Anaheim, how long until the two cars meet?
Bar Model Method
60+651 2 3 4
It will take the cars 4 hours to meet....
“Meet” Problem
0Hours
Total Miles Driven250 375 5000 125
Let x = the time until the two cars meet.
60+65 60+65 60+65
Tool BagFormulas, equations,Vocabulary, etc.
Here’s How…Notes & Examples
Title: Name Date Period
5-2 (Part 3): Rates Using Bar Models
Equation Method65x + 60x = 500
It will take the cars 4 hours to meet....
125x = 500
You Try Sarah leaves her house for her friend’s house walking at 4 mph. At the same time, her friend Jessica leaves her housefor Sarah’s house walking at 3 mph. If they live 21 miles apart,how long will it take until Sarah and Jessica meet?
Let x = the time until the two cars meet.
125x125
500125
=
x = 4