SOLUTION: Terri drove for 3 hours before lunch. After lunch she drove 4 more hours and averaged 15mph more than before lunch. If her total distance was 410 miles, what was her average speed
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Question 1196547: Terri drove for 3 hours before lunch. After lunch she drove 4 more hours and averaged 15mph more than before lunch. If her total distance was 410 miles, what was her average speed before lunch? Answer by ikleyn(52776) (Show Source):
Write the total distance equation
3B + 4*(B+15) = 410 miles total.
where B is her average rate before lunch, in miles per hour.
Simplify the equation and find B
3B + 4B + 60 = 410
7B = 410 - 60
7B = 350
B = 350/7 = 50.
ANSWER. Terri's average rate before lunch was 50 miles per hour.
