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:
63 comments Page 3 of 7.
Sushil said:
7 years ago
Thanks alot for the answer @Sundar.
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?
Divya said:
7 years ago
Good, Thanks @Sundar.
Muklesur said:
7 years ago
2xy/x+y.
2*64*80/64 + 80.
71.111 km/h.
2*64*80/64 + 80.
71.111 km/h.
Rahul said:
7 years ago
@Sundar.
It's so difficult to cut 10240/144.
It's so difficult to cut 10240/144.
Priyadharshini G. said:
7 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:
7 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:
7 years ago
Average speed =2 * 64 * 80/64+80.
= 10240/144.
= 71.11 km/hr.
= 10240/144.
= 71.11 km/hr.
Arjun said:
7 years ago
Why can't we just take the average of the two numbers and divide by 2, since distance travelled at both the speeds is same.
We get the answer as 72.
We get the answer as 72.
Prashanthi said:
7 years ago
Thanks for the solution @Kapil.
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