<PRE><B>Question 214655</B>
If you increase your rate by 25 mph and you are going 25 miles you get there 10 min earlier, what was your initial rate?
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d = rt
25 = rt
25 = (r+25)*(t- 1/6) [10 mins = 1/6 hour]
rt = (r+25)*(t- 1/6) = rt + 25t - r/6 - 25/6
6rt = 6rt + 150t - r - 25
150t = r+25
r = 25/t
150t = (25/t) + 25
150t^2 = 25 + 25t
6t^2 - t - 1 = 0
(3t + 1)*(2t - 1) = 0
t = 1/2 hour (Ignore negative solution)
r = 50 mph
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