SOLUTION: mark was driving on a 245 miles trip. for the first 3 hours he traveled at a steady speed. at teh point realizing he would be late to his destination, he increased his speed by 10m

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Question 270225: mark was driving on a 245 miles trip. for the first 3 hours he traveled at a steady speed. at teh point realizing he would be late to his destination, he increased his speed by 10mph for the remaining 2 hours of the trip. what was his driving speed for each portion of the trip?
Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
Set-up:
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Mark drove for five hors total.
I wrote my equation in terms of his speed during the first three hours.
Equation:3%2AX+%2B+2%2A%28X%2B10%29+=+245
Solution:
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3%2AX+%2B+2%2A%28X%2B10%29+=+245Simplify
3X+%2B+2X+%2B+20+=+245Combine like terms
5X+%2B+20+=+245Subtract 20 from both sides
5X+=+225 Divide both sides by 5
highlight%28X+=+45%29
So now we know that Mark was going 45mph during the fist three hours of the trip.
Then the problem states that during the remaining two hours he went 10mph faster. So during the last two hours of the trip Mark was going 55mph.
Check the answer:
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Plug the values back into the equation
3%2AX+%2B+2%2A%28X%2B10%29+=+245
3%2A%2845%29+%2B+2%2A%2855%29+=+245
135+%2B+110+=+225
highlight%28225+=+225%29