Question

A car travels the first one-third of a certain distance with a speed of 10 km / hr, the next one-third distance with a speed of 20 km / hr, and the last one-third distance with a speed of 60 km/hr. the average speed of the car for the whole journey is :

Answer 1

Hope it helped you .
Mark it as Brainlist.
Have a nice day !

Answer 2

Answer:

18 km/hr

Step-by-step explanation:

Let the distance be 3x

Average speed = (total distance traveled) / (total time taken)

So, let times taken for the first, second and third halves of the journeys be t1, t2, and t3 respectively.

So,$t_1 = \frac{x}{10}$

$t_2 = \frac{x}{20}$

$t_3= \frac{x}{60}$

So, average speed = $\frac{x}{\frac{x}{10}+\frac{x}{20}+\frac{x}{60}}$

So,

= $\frac{3}{\frac{6+3+1}{10}}$

= 18 km/hr

Hence the average speed of the car for the whole journey is 18 km/hr