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 5 of 7.
Damodhar said:
1 decade ago
Average speed = (2*80*64)/(64+80) = 71.11.
Sajnan said:
1 decade ago
This is simple:
First calculate 160/64 = 2.5.
Then 160/60 = 2.
=>2.5+2 = 4.5.
Then calculate 320/4.5 = 71.11.
First calculate 160/64 = 2.5.
Then 160/60 = 2.
=>2.5+2 = 4.5.
Then calculate 320/4.5 = 71.11.
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.
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.
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.
Samiksha said:
1 decade ago
Simply you can aplly the formula ie,
2ab/a+b
then, you will get your answer.
2ab/a+b
then, you will get your answer.
Anshu said:
1 decade ago
Time = distance speed^-1
time = 160 / 64 = 10 / 4 = 2.5 hour
time taken for the second half = 160 / 80 = 2 hour
total time taken = 4.5 hour
total distance = 160 + 160 = 320
speed = distance time^-1
speed = 320 / 4.5 = 3200/ 45 = 355.5555.../5 = 71.1111........
time = 160 / 64 = 10 / 4 = 2.5 hour
time taken for the second half = 160 / 80 = 2 hour
total time taken = 4.5 hour
total distance = 160 + 160 = 320
speed = distance time^-1
speed = 320 / 4.5 = 3200/ 45 = 355.5555.../5 = 71.1111........
Samy said:
1 decade ago
Thank you suguraman.
Shro said:
1 decade ago
Guys,Why ru making it so comlicated...its simple speed=distance by time formula.
then distance is 320 and time is 9/2.
So speed=(320)/(9/2)
which is as per simple calculation
it can also be written as:
320*(2/9)
then distance is 320 and time is 9/2.
So speed=(320)/(9/2)
which is as per simple calculation
it can also be written as:
320*(2/9)
Fatima said:
1 decade ago
Thank you so much Sundar.
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