Question

A train travelled some distance with a speed of 30km/h and return with the speed of 45km/h. Calculate the Average speed

Answer 1

HELLO FRIEND!!!!!!!!!!!!

THANKS FOR YOUR QUESTION @@

WE KNOW THAT,

Average Speed= Total Distance/ Total Time Taken.

But here we don't have the distance we have Speed...........So let's take S1 and S2 ......S2 we taken because the train has returned.

Let,

S1 = 30 km/h

S2 = 45 km/h

Now Suppose the distance will be 90km.

You have a question that how 90 comes.
So I solve your confusion, I taken the LCM of 30 and 45.P

prove ,

5 ⬇ 30 ,45
3 ⬇ 6, ,9
2 ⬇ 2 , 3
3 ⬇ 1 , 3
⬇ 1, 1

5 x 3 x 2 x 3 = 90 ✔

So we will write in two steps
D = distance

So,

D1 = 90

D2 = 90

Hence, the total distance will be

D1 + D2
90 + 90
= 180 km.

And we will calculate the total time...ok

T = Time,

T1 = D1/S1

T1 = 90/30

T1 = 3 hours.

Similarly we can find T2

T2 = D2/S2

T2 = 90/45

T2 = 2 hours.

Therefore the total time are.

T2 + T2 = 3+2
= 5 hours.

So we have calculated the total distance and total time.

So now we can easily find the average Speed.

By using the formula,

Average Speed = Total Distance/ Total Time Taken.

We have the Total Distance= 180 km

And we have Total Time = 5 hours.

Hence,

Average speed = 180/5

= 36 km/h.

Therefore the average speed = 36km/h.

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