Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 9)
9.
A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is:
Answer: Option
Explanation:
| Total time taken = |  |
160 | + | 160 |  hrs. |
= | 9 | hrs. |
| 64 | 80 | 2 |
 Average speed = |
|
320 x | 2 | km/hr |
= 71.11 km/hr. |
| 9 |
Discussion:
64 comments Page 3 of 7.
Priyadharshini G. said:
8 years ago
Given,
Speed 1= 64 km/hr.
Speed 2= 80 km/hr.
Here the distance are same.
Avg. speed = 2 x y /(x+y).
=2 * 64*80/(64+80).
=71.11 km/hr.
Speed 1= 64 km/hr.
Speed 2= 80 km/hr.
Here the distance are same.
Avg. speed = 2 x y /(x+y).
=2 * 64*80/(64+80).
=71.11 km/hr.
Tridib Samanta said:
8 years ago
As the distance of the first half and the second half of the journey is same, i.e. 160 kms.
We can use the formula - [ 2xy / x+y],
=> (2x64x80) / (64+80),
=> 10,240 / 144,
=> 71.1111 km/hr.
Which gives the average speed for the entire journey!
Please note that you could use this formula ONLY IF distances of both halves are SAME.
Here in this problem 160 km each half. So, 320 km total distance of the journey.
All the best!
We can use the formula - [ 2xy / x+y],
=> (2x64x80) / (64+80),
=> 10,240 / 144,
=> 71.1111 km/hr.
Which gives the average speed for the entire journey!
Please note that you could use this formula ONLY IF distances of both halves are SAME.
Here in this problem 160 km each half. So, 320 km total distance of the journey.
All the best!
Pronoi said:
8 years ago
Average speed =2 * 64 * 80/64+80.
= 10240/144.
= 71.11 km/hr.
= 10240/144.
= 71.11 km/hr.
Ajay said:
8 years ago
Total speed 320km/hr.
64km/h + 80km/hr= 144km/hr.
So the average speed is 144/2= 72 km/hr.
64km/h + 80km/hr= 144km/hr.
So the average speed is 144/2= 72 km/hr.
Kartik said:
7 years ago
A car travelled 80km/h. What should be its speed for next 4h, so that the total average speed become 14km/h?
Can anyone answer this with the explanation?
Can anyone answer this with the explanation?
Sushil said:
7 years ago
Thanks alot for the answer @Sundar.
Kiran said:
7 years ago
Thanks, @Sundar.
Girish said:
7 years ago
Well explanation, Thanks.
Aryan said:
7 years ago
How did 9/2 came? please explain me.
Akshay Patel said:
7 years ago
Avg speed of x and y be x+y/2.
Then given that 64+80/2=72.
Then given that 64+80/2=72.
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