Raghu completes his journey in 20 hours. He covers half the distance at 27 km/h and the rest at 54 km/h. What is the length of the journey (in Km)?

Correct option is A

Given:

Total time of journey = 20 hours

Speed for half the distance = 27 km/h

Speed for the remaining half distance = 54 km/h

Formula Used:

Time = $$\frac{\text{Distance}}{\text{Speed}}$$​​

Solution:

Let the total distance be 2d km. This means each half is 'd' km.

Time taken for the first half of the journey: Time1 =$$\frac{\text{Distance}}{\text{Speed}}$$​= $$\frac{d }{ 27 }$$​hours

Time taken for the second half of the journey: Time2 =$$\frac{\text{Distance}}{\text{Speed}}$$​= $$\frac{d }{ 54}$$​hours

Total time taken for the journey: Time1 + Time2 = 20 hours

$$\frac{d }{ 27 } +\frac{d }{54 }$$​= 20

$$\frac{3d }{54}$$​= 20

d = 20$$\times$$​ 18 = 360 km

Total length of the journey (2d): 2$$\times$$ 360 km = 720 km​

Therefore, the length of the journey is 720 km.

Option (A) is right.