Question

A bus travels 150km is one dimensional motion with 25kmph,next 200km with 50 kmph .what must its speed in last 150 km such that net average speed for 500km is 20kmph??!!please urgent

Answer 1

Answer:

10 km/hr in last 150 kms

Explanation:

avg speed=total dist/total time

=150+200+150/(150/25+200/50+150/x)=20

solving this X=10

Answer 2

Answer:

The speed(V3) in last 150 km is 7.5km/h .

Explanation:

Concept: Average speed = Total distance/ Time taken

Given:

D1=150km ,. V1. = 25 km/h

D2= 200km;. V2= 50km/h

D3= 150km;. V3= ?

Davg= 500;. Vavg= 20km/h

Find:

The speed(V3) in last 150 km.

Step By step explanation:

Average speed = Total distance/ Time taken

T1 , is the time taken moving Distance D1 .

Then,

T1=D1/V1

As same as,

T2=D2/V2

and T3=D3/V3

Let us assume V3 as X

Vavg= D1+D2+D3/(T1+T2+T3)

Vavg= D1+D2+D3/(D1/V1)+(D2/V2)+(D3/V3)

20=150+200+150/(150/25)+(200/50)+(150/X)

20=500/6+4+150/X

6+4+150/X= 25

150/X= 20

150/20=X

X= 7.5km/h

The speed(V3) in last 150 km is 7.5km/h

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