[poll id=”65″]
ANSWER: B. 58.4 mph
This type of question is a typical one to be seen in QR.
Speed is equivalent to distance over time: Speed = (Distance/Time).
The total distance of this trip is 150+150=300 miles
Break down the question into 2 components, one for each speed and distance traveled.
First 150 miles:
Time = (Distance / Speed) = (150/70)=2.14 hours
Second 150 miles:
Time= (Distance / Speed) = (150/50)=3.0 hours
Total time is therefore: 2.14+3.0=5.14 hours
Thus, returning back to the Speed=(distance/time)
Speed=(Distance/Time)=(300 miles)/(5.14 hours)= 58.4 miles per hour