SOLUTION: Sam took off on his motorcycle to Salt Lake City at the same time his Dad left for Salt Lake City in his semi. After 8 hours of driving, Sam was 120 miles ahead of his Dad. How fa

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Question 863075: Sam took off on his motorcycle to Salt Lake City at the same time his Dad left for Salt Lake City in his semi. After 8 hours of driving, Sam was 120 miles ahead of his Dad. How fast was Sam traveling if his Dad was driving 50 mph?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = Sam's speed in mi/hr
Let +d+ = distance in miles Dad travels
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Sam's equation:
(1) +d+%2B+120+=+s%2A8+
Dad's equation:
(2) +d+=+50%2A8+
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(2) +d+=+400+
and, by substitution:
(1) +400+%2B+120+=+s%2A8+
(1) +8s+=+520+
(1) +s+=+65+
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Sam was traveling 65 mi/hr