Mixture and Motion Problems: Charts Strategy
That's because they both use the same style charts as one of the most effective strategies.
MIXTURE PROBLEMS:
You have to create a chart that has THREE columns and rows.
Top Row: Prices/Percentages
Middle Row: Volumes: (x, y and the total number)
Bottom row: Multiply everything from the top and down, and put the result in the appropriate box.
It sounds very confusing, which is why I will provide a drawing for the example problem right now.
Example Problem:
Apple Jack has wants to have a 34 gallon apple cider batch. Blend 1 has 3% pure apple juice, and Blend 2 has 58% pure apple juice. She wants her final batch to have 36% pure apple juice. How much should she use?
Chart:
IMPORTANT:
- "Equation 1" is just: x + y = 34
- "Equation 2" is just: 0.03x + 0.58y = 12.24
Now solve for x and y using system of linear equations:
0.03x + 0.58y = 12.24
x + y = 34
...Let's use substitution for this one.
y = 34 - x
0.03x + 0.58(34 - x) = 12.24
0.03x + 19.72 - 0.58x = 12.24
-0.55x = -7.48
x = 13.6
y = 34 - 13.6
y = 20.4
Apple Jack will need 13.6 gallons of Blend 1 and 20.4 gallons for Blend 2.
As long as you know how to do Algebra and how to organize the chart, this should be very simple. TRUST ME!
RATE PROBLEMS:
Use a chart with TWO rows and THREE columns.
WHAT SHOULD BE IN THE CHART:
First column: Rates (mph, km/h, any number PER time period)
SAME DIRECTION ==> Speed of A + Speed of B (except when it's different objects like trains)
Environment helps you move.
OPPOSITE DIRECTION ==> Speed of A - Speed of B
Environment prevents you from moving but you still move.
Second column: Time (hours, minutes, seconds, any time measurement)
Third Column: Distance
(It could already be given, or it is the product of the first two columns)
Example Problem:
Fluttershy is really tired. She is flying with the wind towards Cloudsdale for 2 hours. She comes back flying against the wind from Cloudsdale, just to bring Pinkie Pie cupcakes for 3 hours. In total, she travels 192 miles. (She went down the same path twice in this problem!) What is the speed of Fluttershy and the speed of the wind?
DEFINE YOUR VARIABLES!
f = Speed of Fluttershy
w = Speed of Wind
Also, 192/2 = 96, each path was equal, remember?
Total round trip = distance/2
Solve for f and w using system of linear equations:
2(f + w) = 96 ==> f + w = 48
3(f - w) = 96 ==> f - w = 32
2w = 16
w = 8
f = 40
Fluttershy's speed is 40 mph and the wind speed is 8 mph.
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