Question

Ques. a body covers one third of the journey with speed 10km/h ,next one third with speed 20km/h and last one third with speed 60km/h. calculate the average speed during the whole journey.
PLEASE ANSWER IN HAND WRITTEN FORM NOT IN TYPED FORM

Answer 1

A car travels the first 1/3 of a certain distance with speed of 10km/h

A car travels the first 1/3 of a certain distance with speed of 10km/h the next 1/3 distance with a speed of 20km/h and the last 1/3 distance with a speed of 60km/h the average speed of the car for whole journey is

i know the solution but i want to find out where did i mistake

now we want to find out average speed

avg speed = total distance/total time

now let total distance be x

first x*1/3

all three distance is x/3+x/3+x/3

now total time = speed/distance

total time = x/3/10+x/3/20+x/3/60

equation should be

x/3+x/3+x/3

avg speed = x/3/10+x/3/20+x/3/60

but answer is wrong please explain me how it is wrong