Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 2)
2.
An aeroplane covers a certain distance at a speed of 240 kmph in 5 hours. To cover the same distance in 1
hours, it must travel at a speed of:
hours, it must travel at a speed of:Answer: Option
Explanation:
Distance = (240 x 5) = 1200 km.
Speed = Distance/Time
Speed = 1200/(5/3) km/hr. [We can write 1 hours as 5/3 hours]
 Required speed = |
 |
1200 x | 3 |  km/hr |
= 720 km/hr. |
| 5 |
Discussion:
162 comments Page 7 of 17.
Ramkumar said:
1 decade ago
Sir/madam please explain in detail. I cant understand.
Sreenath said:
1 decade ago
Hi, we know that speed=distance/time
Here distance is constant for different times
so speed o< 1/time
i.e
s1/s2=t2/t1
=> s2=s1*(t1/t2)
=> s2=240*[5/(5/3)]
=> s2=240*3
=> s2=720
here s2 is the speed when time is 5/3
remember when distance is constant speed o< 1/time
if speed constant time o< distance
if time is constant speed o< distance
Thanks.
Here distance is constant for different times
so speed o< 1/time
i.e
s1/s2=t2/t1
=> s2=s1*(t1/t2)
=> s2=240*[5/(5/3)]
=> s2=240*3
=> s2=720
here s2 is the speed when time is 5/3
remember when distance is constant speed o< 1/time
if speed constant time o< distance
if time is constant speed o< distance
Thanks.
Lakhan said:
1 decade ago
I have not understood the step where you have taken 1200*3/5 instead of 1200*5/3 ?
Nikita said:
1 decade ago
Another way
This is an example of inverse variation
So,
240*5=5/3*x
x=720
This is an example of inverse variation
So,
240*5=5/3*x
x=720
Honey said:
1 decade ago
Time decrease by 3times. 5/3=1*2/3.
Therefore speed increases by 3 times=3x240=720km/hr.
Therefore speed increases by 3 times=3x240=720km/hr.
Dilip said:
1 decade ago
Those who says Answer as 720 please read the question. Its given that speed for a time of 1Hr should be foun out, not for 1+ (2/3) hrs.
Joseph said:
1 decade ago
Even if the aeroplane travels in the speed of 720km/hr it can the distance of 1152km..... As the nearest answer is 720km/hr.
Josh Koikkara said:
1 decade ago
Speed: 240Km/Hr
Time: 5Hrs
Distance= Speed*Time
D= 240*5
=1200m
Given, Time=5/3Hr
Speed= Distance/Time
= 1200/(5/3)
= 1200*3/5
=720 Km/Hr
Time: 5Hrs
Distance= Speed*Time
D= 240*5
=1200m
Given, Time=5/3Hr
Speed= Distance/Time
= 1200/(5/3)
= 1200*3/5
=720 Km/Hr
Nil said:
1 decade ago
Those who says answer as 720, why you are taken time as 5/3 hr instead of 1 hr as given in d example.
Abhishek sunny said:
1 decade ago
Those who says the answer is 720kmph please concentrate on my statement----.
If the answer is 720kmph then it means if we multi 720kmph with the given time of 1hr then we get the this which is 1200km isn't.
But did we get it?!
If the answer is 720kmph then it means if we multi 720kmph with the given time of 1hr then we get the this which is 1200km isn't.
But did we get it?!
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers