SOLUTION: Kathryn drove her rig 3 hours before dawn and 4 hours after dawn. Her average speed was 6 miles per hour more in the dark and she covered 410 miles altogether. What was her speed

Question 605488: Kathryn drove her rig 3 hours before dawn and 4 hours after dawn. Her average speed was 6 miles per hour more in the dark and she covered 410 miles altogether. What was her speed after dawn in miles per hour?
I need to know teh correct formula as well as how to find this answer. Thank you.

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Kathryn drove her rig 3 hours before dawn and 4 hours after dawn. Her average speed was 6 miles per hour more in the dark and she covered 410 miles altogether. What was her speed after dawn in miles per hour?
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Before dawn DATA:
time = 3 hrs ; rate = x+6 mph ; distance = 3x+18 miles
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After dawn DATA:
time = 4 hrs ; rate = x mph ; distance = 4x miles
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Equation:
3x+18 + 4x = 410 miles
7x = 392 miles
x = 56 mph (speed after dawn)
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Cheers,
Stan H.
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