A man drives his car for 24 km at a speed of 48 km/h, and for the next 1.5 hours he drives at a speed of 80 km/h. Find his average speed (in km/h) for the entire journey.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 72.
Given that
A man drives his car for 24 km at a speed of 48 km/h
For the next 1.5 hours, he drives at a speed of 80 km/h
Formula used
Distance = Speed × time
Average speed = Total distance/Total time taken
Calculation
Total distance = 24 + 1.5 × 80 = 24 + 120 = 144 km
Total time taken = 24/48 + 1.5 = 0.5 + 1.5 = 2 hours
Hence, average speed = 144/2 = 72 km/h