Difference between revisions of "004 Sample Final A, Problem 12"

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(Created page with "<span class="exam"> Set up, but do not solve the following word problem. Two private airplanes travel toward each other from cities that are 780 km apart at speeds of 190 km/h...")
 
 
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<span class="exam"> Set up, but do not solve the following word problem. Two private airplanes travel toward each other from cities that are 780 km apart at speeds of 190 km/hr and 200 km/hr. They left at the same time. In how many hours will they meet?
 
<span class="exam"> Set up, but do not solve the following word problem. Two private airplanes travel toward each other from cities that are 780 km apart at speeds of 190 km/hr and 200 km/hr. They left at the same time. In how many hours will they meet?
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{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
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! Foundations
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|-
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|What is the formula for distance?
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|-
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|Answer:
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|-
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|The formula for distance is d=rt where r is the rate and t is the time.
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|}
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Solution:
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{| class = "mw-collapsible mw-collapsed" style = "text-align:left;"
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! Step 1:
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|-
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|The distance formula for the plane traveling 190km/hr is <math> 190t=d</math>.
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|}
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{|class = "mw-collapsible mw-collapsed" style = "text-align:left;"
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! Step 2:
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|-
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|The other plane starts off 780km away from the first plane. So, this plane's distance is 780-d where d is the distance of the first plane.
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|-
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|So, the distance formula for this second plane is <math>200t=780-d</math>.
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|}
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{|class = "mw-collapsible mw-collapsed" style = "text-align:left;"
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! Step 3:
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|-
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|Now, adding these two equations together, we get <math> 390t=780</math>. So, <math>t=2</math> hours.
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|}
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{|class = "mw-collapsible mw-collapsed" style = "text-align:left;"
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! Final Answer:
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|-
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|2 hours
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|}
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[[004 Sample Final A|<u>'''Return to Sample Exam</u>''']]

Latest revision as of 16:07, 5 May 2015

Set up, but do not solve the following word problem. Two private airplanes travel toward each other from cities that are 780 km apart at speeds of 190 km/hr and 200 km/hr. They left at the same time. In how many hours will they meet?

Foundations
What is the formula for distance?
Answer:
The formula for distance is d=rt where r is the rate and t is the time.


Solution:

Step 1:
The distance formula for the plane traveling 190km/hr is .
Step 2:
The other plane starts off 780km away from the first plane. So, this plane's distance is 780-d where d is the distance of the first plane.
So, the distance formula for this second plane is .
Step 3:
Now, adding these two equations together, we get . So, hours.
Final Answer:
2 hours

Return to Sample Exam

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