SOLUTION: One morning, Justin drove 5 hours before stopping for lunch at a pizza place. After lunch, he increased his speed by 10 miles per hour. If he completed a 430-mile trip in eight hou

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Question 1165526: One morning, Justin drove 5 hours before stopping for lunch at a pizza place. After lunch, he increased his speed by 10 miles per hour. If he completed a 430-mile trip in eight hours of driving time, how fast did he drive before stopping for lunch?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
speed was x mph
drove 5x miles before lunch
drove x+10 mph after lunch for 3 hours or 3(x+10) or 3x +30 miles
The sum is 8x+30=430
8x=400
x=50 mph ANSWER
250 miles before lunch
x+10=60 mph
180 miles after lunch