suppose a car is driven from town A to town B from town B to town C and from town C to town D which have equal distances at average speeds 20km/hr,60km/hr and 120km/hr respectively,what is the average speed for the whole journey

Avg. Speed = (20+60+120)/3 = 66.67 km/h.

To find the average speed for the whole journey, we need to consider the total distance traveled and the total time taken.

First, let's calculate the distances traveled between the towns:

Distance from A to B = Distance from B to C = Distance from C to D (given)

Now, let's calculate the total distance traveled:

Total distance = Distance from A to B + Distance from B to C + Distance from C to D

Next, let's calculate the time taken for each leg of the journey:

Time taken from A to B = Distance from A to B / Speed from A to B

Similarly,

Time taken from B to C = Distance from B to C / Speed from B to C

Time taken from C to D = Distance from C to D / Speed from C to D

To calculate the average speed, we need to find the total time taken for the journey. The total time is the sum of the time taken for each leg of the journey.

Total time = Time taken from A to B + Time taken from B to C + Time taken from C to D

Finally, we can calculate the average speed:

Average speed = Total distance / Total time

By plugging in the values we have gathered, we can find the average speed for the whole journey.