Question

A car travels a certain distance at 32 km/h and comes back at 68 km/h. what is the average speed for total journey?

Answer 1

Hello friend!!!!!!!!!!!!

Thanks for your question???????

Generally we know that,

Average Speed = Total distance/ Total time taken.

But here we have Speed...

So let's take S1 and S2 as the car returned.

S = Speed

Let,

S1 = 32 km/h

S2 = 68 km/h

Suppose that the distance will be 544 km.
544 is the LCM of 32 and 68

that's why we have taken 544.

So next we write it in two steps.

Distance = D

So ,

D1 = 544

D2 = 544

hence the total distance will be,

D1 + D2

= 544 + 544

= 1088 km.

So we have calculated the total distance and now we will calculate the total time.

Time = T

T1 = D1/S1

T1 = 544/32

T1 = 17 hours.

Similarly,

T2 = D2/S2

T2 = 544/68

T2 = 8 hours.

So the total time
= T1 + T2
= 17+8= 25 hours.

Now we easily find the average speed.

By using the formula,

Average Speed = Total distance/ Total Time taken.

Average Speed = 1088/25

= 43.52 km/h.

Therefore the average speed = 43.52 km/h.

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......... I hope this will helps you.............