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 2 of 7.
Ravi said:
6 years ago
At 64 km/hr it will take 2.5 hrs for travelling 1st 160 km and at 80 km/hr it will take 2 hrs for travelling 2nd 160 km.
So, the total 4.5 hrs for 320 km.
So 320 / 4.5 === 71.11 km Average speed.
So, the total 4.5 hrs for 320 km.
So 320 / 4.5 === 71.11 km Average speed.
(1)
Jeevan said:
1 decade ago
We have to use like this also,
Total distance = 320.
1st half = 160.
2nd half = 160.
1st half speed = 64km/hr.
2nd half speed = 80km/hr.
Avg speed of 320km(dist) = 2*(64*80)/64+80 = 71.11 km/hr.
Total distance = 320.
1st half = 160.
2nd half = 160.
1st half speed = 64km/hr.
2nd half speed = 80km/hr.
Avg speed of 320km(dist) = 2*(64*80)/64+80 = 71.11 km/hr.
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.
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?
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.
Aby said:
12 months ago
Avg speed = TD/TT.
Total Distance (TD) = 160 + 160 = 320 km.
Total Time (TT) =160/64 + 160/80 = 9/2 hr.
Avg speed = 320 * 2/9 = 71.11km/hr.
Total Distance (TD) = 160 + 160 = 320 km.
Total Time (TT) =160/64 + 160/80 = 9/2 hr.
Avg speed = 320 * 2/9 = 71.11km/hr.
(7)
Balamurugan said:
8 months ago
@All.
Start 1st half 160/64 = 2.5hr
second half 160/80 = 2hr
2.5 + 2 = 4.5hr.
Speed = distance/time.
s = 160 + 160/4.5
= 320/4.5 = 71.11.
Start 1st half 160/64 = 2.5hr
second half 160/80 = 2hr
2.5 + 2 = 4.5hr.
Speed = distance/time.
s = 160 + 160/4.5
= 320/4.5 = 71.11.
(13)
Paarth said:
4 years ago
First 160 km: Speed is 64 kmph.
Second 160 km:- Speed is 80 kmph.
So, just use Average speed = (2xy)/x+y = (2*64*80)/64+80 = 71.11 kmph.
Second 160 km:- Speed is 80 kmph.
So, just use Average speed = (2xy)/x+y = (2*64*80)/64+80 = 71.11 kmph.
(2)
Javid Mir said:
1 decade ago
Simple;
Average speed = 2xV1xV2/V1+V2.
Avg. Speed = 2x64x80/64+80.
Avg. Speed = 2x64x80/144.
Solving we get; avg speed = 71.1 Km/hr.
Average speed = 2xV1xV2/V1+V2.
Avg. Speed = 2x64x80/64+80.
Avg. Speed = 2x64x80/144.
Solving we get; avg speed = 71.1 Km/hr.
Siva said:
1 decade ago
Speed=distance/time.
A) first time: 160/64 = 2.5.
B) second time: 160/80 = 2.
a+b = 2. 5+2 = 4.5.
Average speed=320/4.5 = 71.11.
A) first time: 160/64 = 2.5.
B) second time: 160/80 = 2.
a+b = 2. 5+2 = 4.5.
Average speed=320/4.5 = 71.11.
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