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A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey?
Most Upvoted Answer
A parcel lorry came into city with the average speed of 90km/hr. On th...
As we know, Speed = Distance / Time, Therefore Average Speed = Total Distance / Total Time.
Let us assume, Time taken to come to the city = T1
Time taken to go back = T2
Speed while coming to city = V1
Speed while going back = V2
Therefore, T1 = D / V1
and T2 = D / V2
Formulae for Average Speed =>> Average Speed = Distance (coming to city) + Distance (going back)
-------------------------------------------------------------------
T1 + T2
Let us now substitute the formula of T1 and T2, respectively:-
Average Speed = D + D
------------------
D/V1 + D/V2
Average Speed = 2D
----------------------
D (1/V1 + 1/V2)
We can now cancel 2D by the denominator D,
Average Speed = 2
----------------------
1/V1 + 1/V2
Now we can substitute the actual values of V1 and V2, as per the information given in the question,
Average speed = 2
-----------------------
1/90 + 1/60
Average speed = 2
---------------------
5/180
Average Speed = 2 x 180/5
Average Speed = 360/5
Average Speed = 72 km/hr.
Therefore the average speed would come out to be 72 Kms/Hr.
Community Answer
A parcel lorry came into city with the average speed of 90km/hr. On th...
Average speed = total distance / total time... suppose distance between home to city is D..... ==> t1 = D / V1 & t2= D / V2 ===> Average speed = D + D / t1 + t2===> = 2 D / [ ( D / V1 ) + ( D / V2 ) ] = 2 D / D [ ( 1 / V1 ) + ( 1 / V2 ) ] == 2 / [ ( 1 / 90 ) + ( 1 / 60 ) ] = 2 * 90 * 60 / (90 + 60 )= 10800 / 150 =72 km / hr ........IS THR YOUR ANSWERR💯💯💯
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A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey?
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A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey? for Class 7 2024 is part of Class 7 preparation. The Question and answers have been prepared according to the Class 7 exam syllabus. Information about A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey? covers all topics & solutions for Class 7 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey?.
A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey? for Class 7 2024 is part of Class 7 preparation. The Question and answers have been prepared according to the Class 7 exam syllabus. Information about A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey? covers all topics & solutions for Class 7 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A parcel lorry came into city with the average speed of 90km/hr. On the return journey speed of lorry is 60km/hr.Find the averagespeed of entire journey?.
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