SOLUTION: A dreaded word problem. This is out of the Algebra textbook 5th edition by Dugopolski. Chapter 8.3 page 550 #85. Here's the problem:
Erin was traveling across the desert on her bi
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Erin was traveling across the desert on her bi
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Question 235021: A dreaded word problem. This is out of the Algebra textbook 5th edition by Dugopolski. Chapter 8.3 page 550 #85. Here's the problem:
Erin was traveling across the desert on her bicycle. Before lunch she traveled 60 miles (mi); after lunch she traveled 46 miles. She put in 1 hour more after lunch than before lunch, but her speed was 4 mph slower than before. What was her speed before lunch and after lunch?
The answer is in the back of the book, and it is:
Before -5 + the square root of (265) or 11.3 mph;
After -9 + the square root of (265) or 7.3 mph
We are just completely confused about how to get the solution. We attempted to set it up in a distance=rate*time chart, but are not having any luck with that. Could you please show how to get a solution to this problem? Thank you very much in advance!!
Sandy :-) Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! You need 2 equations, 1 for each part of the trip
given: mi mi hrs mi/hr
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Now I can rewrite the equations
(1)
(2)
This is 2 equations and 2 unknowns, so it's solvable
(2)
And, since ,
(2)
(2)
Now go back to (1)
(1)
plug this back into (2)
(2)
Multiply both sides by
This can be solved by completing the square
The left side is a perfect square
Take the square root of both sides mi/hr
And, since mi/hr
