The question given below is a quant problem solving question in Speed Time and Distance.
Steve traveled the first 2 hours of his journey at 40 mph and the remaining 3 hours of his journey at 80 mph. What is his average speed for the entire journey?
- 60 mph
- 56.67 mph
- 53.33 mph
- 64 mph
- 66.67 mph
The correct choice is (D) and the correct answer is 64 mph
Average speed of travel =
Total distance traveled by Steve = Distance covered in the first 2 hours + distance covered in the next 3 hours.
Distance covered in the first 2 hours = speed * time = 40 * 2 = 80 miles
Distance covered in the next 3 hours = speed * time = 80 * 3 = 240 miles
Therefore, total distance covered = 80 + 240 = 320 miles
Total time taken = 2 + 3 = 5 hours.
Hence, average speed =
= 64 miles per hour.
If Steve had traveled equal amount of time at 40 mph and 80 mph, then his average speed will be the arithmetic mean (or simple average) of the two speeds.