SOLUTION: One morning, Justin drove 5 hours before stopping to eat lunch at Chick-fil-A. After lunch, he increased his speed by 10 mph. If he completed a 450-mile trip in 10 hours of driving

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Question 1121630: One morning, Justin drove 5 hours before stopping to eat lunch at Chick-fil-A. After lunch, he increased his speed by 10 mph. If he completed a 450-mile trip in 10 hours of driving time, how fast did he drive in the morning?
Answer by ikleyn(52787)   (Show Source): You can put this solution on YOUR website!
.
Let x = "how fast did he drive in the morning".


Then his speed after lunch was (x+10) mph.


The equation is


5x + (10-5)*(x+10) = 450  miles.


5x + 5*(x+10) = 450

5x + 5x + 50 = 450

10x = 450-50 = 400   ====>  x =  = 40 miles per hour was his speed in the morning.

Solved.

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