A person divides his total route of journey into three equal parts and decides to travel the three parts at the speeds of 80 km/h, 60 km/h and 30 km/h, respectively. What is the average speed during the journey?

Correct option is D

Given:
The three parts at the speeds of 80 km/h, 60 km/h and 30 km/h
Formula Used:
Average Speed = $$\frac{ (Total \ Distance)}{(Total \ Time)}$$​​
Solution:
Lets the distance of each equal parts be 240km
Total distance = 3 x 240 = 720km
Time taken to cover 240km at 80km/hr = $$\frac{240}{80} = 3hrs$$​​

Time taken to cover 240km at 60km/hr  $$= \frac{240}{60} = 4hrs$$​​
Time taken to cover 240km at 30km/hr = $$\frac{240}{30} = 8hrs$$​​
Total time taken = 3+4+8= 15hrs
Average Speed =$$\frac{720}{15}$$​ = 48km/hr