SOLUTION: I am having a problem soving this equation. On a recent trip, Sarah's car traveled 20mph faster on the first 110 miles than it did on the remaining 80 miles. The total time for t

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Question 144742: I am having a problem soving this equation. On a recent trip, Sarah's car traveled 20mph faster on the first 110 miles than it did on the remaining 80 miles. The total time for the trip was 4hr. Find the speed of Sarah's car on the first part of the trip. This is how much I know d=rt
First part: r= 20 + x d = 110
Second part: r = x d=80
Now I am stuck. Please help me
Thank you
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
d = rt let x be the speed on the last part of the trip
100 = (r+20)t[1]
t[1] = 100/(r+20)

80 = rt[2]
t[2] = 80/r
t[1] + t[2] = 4
%28100%2F%28r%2B20%29%29+%2B+80%2Fr+=+4+
%28%28100+r%29+%2B+80%28r%2B20%29%29%2F%28r+%2A+%28r%2B20%29%29+=+4+
I bet you can take it from here.
Let me know if you can't