Ramesh, on his way to his hometown, travelled the first 250 km at a speed of 75km/h and the next 250 km at a speed of 85 km/h. Find the average speed for the whole journey(correct to 2 decimal places)
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 79.69km/h.
Here, the distance of the first part and the second part is the same.
x = 75 km/h and y = 85 km/h
Average speed = (2xy)/(x + y)
= (2 × 75 × 85)/(75 + 85)
= (2 × 75 × 85)/160
= 79.6875 km/h
= 79.69 km/h (approx)
Therefore, the average speed for the whole journey is 79.69 km/h.