Question

while travelling from Hyderabad to Bangalore by a car,the driver covers one fourth of the distance at 60kmph, one third of the distance at 80kmph, one sixth of the distance at 100kmph and the remaining distance at 50kmph. then his average speed for the whole journey, in kilometres per hour is

Answer 1

Answer:

Step-by-step explanation:

Let the total distance be x.

Time = Distance / speed

Distance covered at 80 km/h is :

= 1/3x

Time taken = 1/3x × 1/80 = 1/240x

Distance covered by 60 km/h is :

= 1/4x

Time = 1/4x × 1/60 = 1/240x

Distance covered at 100km/h is :

= 1/6x

Time taken = 1/6x × 1/100 = 1/600x

Distance covered at 50km/h is :

1 - (1/4 + 1/3 + 1/6) = 1/4x

Time = 1/4x × 1/50 = 1/200x

Total time taken is :

1/240x + 1/240x + 1/600x + 1/200x = 3/200x

Average speed = Total distance / Total time

This is given by :

x ÷ 3/200x

= x × 200/3x = 200/3

= 66.67 km/h