Question 516924
Wendy drives for a number of hours at 70 miles per hour.
 Road construction appears and traffic slows and she drives at 50 miles per hour.
 She travels at 50 miles per hour for .5 hours longer then she traveled at 70 miles per hour.
 The difference in the distance traveled at 50 mph and 70 mph is 5 miles.
 How long was Wendy driving at 50 mph?
:
Let t = driving time at 50 mph
From the information given, we know:
(t-.5) = driving time at 70 mph
:
Write a distance equation dist = speed * time:
:
50mph dist - 70mph dist = 5 miles
50t - 70(t-.5) = 5
50t - 70t + 35 = 5
-20t = 5 - 35
-20t = -30
t = {{{(-30)/(-20)}}}
t = +1.5 hrs at 50 mph
:
:
Confirm this by finding the distance driven at each speed
50*1.5 = 75 mi
50 * 1 = 70 mi
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differs  5 min