Ram travelled an equal distance with the speed of 40 km/hr, 45 km/hr and 60 km/hr. What is the average speed of Ram during the whole journey? Correct to two decimal places.

Correct option is D

Given: 

Distance = Equal 

$$S_1 =$$  40 km/h

$$S_2 =$$ 45 km/h

$$S_3 =$$60 km/h  

Formula Used:

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

Solution:

Let the distance = x km

Then 

Average speed = $$\frac{3x } { \frac{x}{40}+ \frac{x}{45} + \frac{x}{60}}$$  

                          = $$\frac{ 3 \times 360} { 9 + 8 + 6 }$$  

                         = $$\frac{ 1080}{23 }$$  

                         = 46.96 km/h