Problema Solution
Sally was able to drive an average of 28 miles per hour faster in her car after the traffic cleared. She drove 23 miles in traffic before it cleared and then drove another 255 miles. If the total trip took 6 hours, then what was her average speed in traffic?
Answer provided by our tutors
Let 'v' represent the average speed in traffic.
After the traffic cleared her average speed was 'v + 28'.
d1 = 23 mi the distance in the traffic
d2 = 255 the distance after traffic cleared
t = 6 hr the total time of the trip
Since time = distance/speed we have:
d1/v + d2/(v + 28) = t
23/v + 255/(v + 28) = 6
........
click here to see the equation solved for v
........
v = 23 mph
Sally's average speed in the traffic was 23 mph.