A student walked 6 km from his house to reach the metro station, then boarded a metro that has an average speed of 60km/h, and reached the destination. It took 3 hours for the entire journey. If the average speed of the entire journey is 32 km/h, then the speed of walking is ______.
Answer & explanation
Correct answer: option 4
Average speed of whole journey = 32 km/h
Time taken = 3 hours
Total distance = 32 × 3 = 96 km
Average speed of metro = 60 km/h
Let time taken by metro = t hours
So , Distance = 60 × t = 60t km
According to question ,
6 + 60 × t = 96
60x = 96 – 6
60x = 90
x = \(\frac{90}{60}\)
x = 1.5 hrs
Time taken to cover 6 km distance = 3 – 1.5 = 1.5 hrs
Walking speed = \(\frac{Distance}{Time}\)
= \(\frac{6}{1.5}\) = 4 km/hr
So , Average speed of walking is 4 km/hr