Problema Solution
During the first part of a trip, Adrian drove 34 miles at a certain speed. Adrian drives another 34 miles on the second part of the trip at a speed 5 mph faster. Driving time for the entire trip was 104 mins. Find the rate at which Adrian drove during the first part of the trip.
Answer provided by our tutors
Let
v = the rate at which Adrian drove during the first part of the trip, v>=0.
v + 5 = the rate at which Adrian drove during the second part of the trip
d = 34 mi the distance of each part of the trip
t = 104 min = 104/60 hr
Since speed = distance/time follows time = distance/speed.
The time of the first part of trip plus the time of the seconds part of the trip equals t:
d/v + d/(v + 5) = t
34/v + 34/(v + 5) = 104/60
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click here to see the equation solved for v
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v = 36.89 mph
We need to ignore the negative root since the rate can only be positive.
Adrian drove with 36.89 mph during the first part of the trip.