Question

A thief drives his motorcycle at a speed of x km/hr. The Policemen started chasing him in a jeep after 4

hours and catches in 4 hours. If the average speed of jeep of policemen is 40 km/hr, then calculate the

speed in km/hr for the thief's motorcycle​

Answer 1

Given :

Speed of motorcycle = x km/hr

Speed of jeep of policemen = 40 km/hr

Policemen started chasing thief after 4 hour and catches the thief in 4 hour.

To find :

Speed of motorcycle.

Solution :    

When policemen catches the thief jeep then distance traveled by both thief and policemen will be same.

Time taken by thief = 4+4 = 8 hour

Distance traveled in hour hour = x×8 = 8x km

Time taken by policemen = 4 hour

Distance traveled by policemen jeep = 4×40 = 160 km

As both the distance is same

Therefore $8x=160$

x = 20 km/hr

So speed of thief will be 20 km/hr

Answer 2

Given :

• A thief drives his motorcycle at a speed of x km/hr. The Policemen started chasing him in a jeep after 4 hours and catches in 4 hours. If the average speed of jeep of policemen is 40 km/hr.

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Find :

• Calculate the speed in km/hr for the thief's motorcycle.

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Calculations :

• Time taken:

• Thief = 4 + 4 = 8 hrs.

• Policemen = 4 hrs

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= 4 × 40

= 160 km

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Hence, 160 km is the distance travelled by policemen in his jeep.

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• Finding the speed travelled by thief:

= 160/8

= 20 km/hr

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Therefore, 20 kilometer by hour is the speed of the thief.