Question 1014794: A car traveled at a steady speed for 105 miles. Because of traffic, the driver had to cut her speed in half for the next 42 miles. The total time for the trip was 2 hours and 42 minutes. Find the original speed.
Answer by robertb(5830)   (Show Source):
You can put this solution on YOUR website! Let x = constant original speed, in miles per hour.
Then for first 105 miles, with a rate of x mph, the time traveled was 105/x hours. (From the formula t = distance/speed.)
The last 42 miles was traveled at a rate of x/2 mph as given, so the time traveled is  , or 84/x hours.
Hence, as mentioned in the problem, 
 , after cross-multiplication.
Thus, x = 70 mph, the original speed.
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