A vehicle travels the first 40 km of its journey at an average speed of 60
km/h and the remaining 50km at an average speed of 100 km/h. Find the
average speed of its entire journey.
MY ANSWER IS 75 15/7
I THINK ITS WRONG
HELP ME
Answers
The average speed of its entire journey is 81.8 km/h
Step-by-step explanation:
GIVEN
A vehicle travels the first 40 km of its journey at an average speed of 60 km/h
The remaining 50km at an average speed of 100 km/h
___________________________
TO FIND
The average speed of its entire journey
___________________________
We know that,
Speed = Distance / Time
Distance = Speed × Time
Time = Distance / Speed
___________________________
We know that,
A vehicle travels the first 40 km of its journey at an average speed of 60 km/h
Distance = 40 km
Speed = 60 km/h
Time = ?
We know that,
Time = Distance / Speed
Time = 40 / 60
Time = 0.6
Time = 0.6 hours
___________________________
We know that,
The remaining 50km at an average speed of 100 km/h
Distance = 50 km
Speed = 100 km/h
Time = ?
We know that,
Time = Distance / Speed
Time = 50 / 100
Time = 0.5
Time = 0.5 hours
___________________________
Now
Let's find the average speed of entire journey
We know that,
Distance = 40 km + 50 km
Distance = 90 km
Time = 0.6 hours + 0.5 hours
Time = 1.1 hours
Speed = ?
We know that,
Speed = Distance / Time
Speed = 90 / 1.1
Speed = 81.8
Speed = 81.8 km/h
The average speed of its entire journey is 81.8 km/h
☆Answer☆
Distance travelled at 1st = 40 km
Average Speed = 60 km/h
Time = (Distance/Speed)
= 40/60
= 0.6
• Time taken = 0.6 hour
Distance travelled at 2nd = 50 km
Average Speed = 100 km/h
Time = (Distance/Speed)
= 50/100
= 0.5
• Time taken = 0.5 hour
Now,
Total Distance travelled
= (40+50) km
= 90 km
Total time taken
= (0.6+0.5) hours
= 1.1 hours
• Average Speed
= (Total distance travelled/Total time taken)
= (90/1.1) km/h
= 81.8 km/hr
Hence, the average speed of entire journey is 81.8 km/hr
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