A man travelled four equal distances of 7 km at the speeds of 8 km/hr, 16 km/hr, 24 km/hr and 32 km/hr respectively. What is his average speed?

Correct option is D

​Given:​
Distances = 7 km each, Speeds = 8 km/hr, 16 km/hr, 24 km/hr, 32 km/hr
Formula Used: 

Average speed = $$\frac{Total \ Distance }{Total \ Time}$$   

Solution:
​$$Average \ Speed = \frac{4 \times 7}{\frac{7}{8} + \frac{7}{16} + \frac{7}{24} + \frac{7}{32}} = \frac{384}{25}$$ 

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