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:
35.55 km/hr
36 km/hr
71.11 km/hr
71 km/hr
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 5 of 7.

Divya said:   7 years ago
Good, Thanks @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?

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:   6 years ago
Avg speed of x and y be x+y/2.

Then given that 64+80/2=72.

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.
(1)

Nishit said:   6 years ago
@All.

Average speed means time is constant. So time would be same. Right?

Vijayalakshmi V said:   5 years ago
The average speed = 2xy/(x+y).
where x=64 kmph y = 80 kmph,
Therefore, 2(64)(80)/(64+80) = (8)(80)/9.
= 640/9.
= 71.11 kmph.
(1)


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