A man completes 30 km of a journey at 6 km/h and the remaining 40 km of the journey in 5 h. His average speed for the whole journey is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 7 km/h
Average speed is total distance ÷ total time, not the average of the two speeds, so first find the time of each part.
Time for the first 30 km at 6 km/h: \(30\div6=5\) h
Total distance: \(30+40=70\) km
Total time, with the 5 h of the second part: \(5+5=10\) h
Average speed: \(70\div10=7\) km/h