Aptitude - Time and Distance - Discussion
Discussion Forum : Time and Distance - General Questions (Q.No. 6)
6.
In a flight of 600 km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by 200 km/hr and the time of flight increased by 30 minutes. The duration of the flight is:
Answer: Option
Explanation:
Let the duration of the flight be x hours.
| Then, | 600 | - | 600 | = 200 |
| x | x + (1/2) |
 |
600 | - | 1200 | = 200 |
| x | 2x + 1 |
x(2x + 1) = 3
2x2 + x - 3 = 0
(2x + 3)(x - 1) = 0
x = 1 hr. [neglecting the -ve value of x]
Discussion:
205 comments Page 3 of 21.
Kiran.p said:
2 decades ago
We know that speed=distance/time;
Let us assume time as x,then actual speed=600/x;
Now the time is incremented to 30 min right,
So, now the speed=600/(x+1/2)
Here we take the time in hrs so (x+1/2).
In the problem the speed is reduced by 200km/hr
So the diff btwn speed is equal to 200km/hr.
i.e. 600/x-600/x+(1/2)=200
Let us assume time as x,then actual speed=600/x;
Now the time is incremented to 30 min right,
So, now the speed=600/(x+1/2)
Here we take the time in hrs so (x+1/2).
In the problem the speed is reduced by 200km/hr
So the diff btwn speed is equal to 200km/hr.
i.e. 600/x-600/x+(1/2)=200
(3)
Vijaya lakshmi said:
6 years ago
We know that speed = distance/time;
Let us assume time as x,then actual speed=600/x;
Now the time is incremented to 30 min right,
So, now the speed=600/(x+1/2)
Here we take the time in hrs so (x+1/2).
In the problem, the speed is reduced by 200km/hr
So the diff between speed is equal to 200km/hr.
i.e. 600/x-600/x+(1/2) = 200.
Let us assume time as x,then actual speed=600/x;
Now the time is incremented to 30 min right,
So, now the speed=600/(x+1/2)
Here we take the time in hrs so (x+1/2).
In the problem, the speed is reduced by 200km/hr
So the diff between speed is equal to 200km/hr.
i.e. 600/x-600/x+(1/2) = 200.
(3)
Muzzu said:
6 years ago
T+30 = 600/400,
T+30/60 = 3/2,
T+1/2 = 3/2,
T= 3/2-1/2,
T= 1 hour.
T+30/60 = 3/2,
T+1/2 = 3/2,
T= 3/2-1/2,
T= 1 hour.
(3)
Harika said:
4 years ago
It's simple way using average model.
2 * X * Y/(X+Y) = 2 * 200 * 600/200 * 600.
=>2.
In 30minutes we have to find?
2 * 30minutes = 60minutes
60minutes is gone to 1hour.
Ans: 1hour.
2 * X * Y/(X+Y) = 2 * 200 * 600/200 * 600.
=>2.
In 30minutes we have to find?
2 * 30minutes = 60minutes
60minutes is gone to 1hour.
Ans: 1hour.
(3)
Varsh said:
4 years ago
Its simple only, take LCM of (600/x)-(1200/(2x+1)) = 200,
you get (2x+1)(600) - 1200x = 200(2x^2 +x),
2x^2 +x = 3.
which is nothing but x(2x+1) = 3.
you get (2x+1)(600) - 1200x = 200(2x^2 +x),
2x^2 +x = 3.
which is nothing but x(2x+1) = 3.
(3)
ANKIT said:
4 years ago
Thanks @Kiran.
(3)
Shraddha Patel said:
3 years ago
Thanks, @Ravi.
(3)
Diya said:
5 years ago
Given distance =600.
Let initial speed and time be s & t.
So,speed s=600/t.
Now given speed is reduced by 200,so s becomes s-200 and time is increased by 30 mins, So t becomes t+(30/60) in hrs.
Distance= speed*time.
600=(s-200)(t+(30/60)).
Sub for s ,600=(600/t -200)(t+(30/60)).
600=200[(3/t)-1](3t/2).
1=(3/2)-(t/2).
t = 1.
Let initial speed and time be s & t.
So,speed s=600/t.
Now given speed is reduced by 200,so s becomes s-200 and time is increased by 30 mins, So t becomes t+(30/60) in hrs.
Distance= speed*time.
600=(s-200)(t+(30/60)).
Sub for s ,600=(600/t -200)(t+(30/60)).
600=200[(3/t)-1](3t/2).
1=(3/2)-(t/2).
t = 1.
(2)
Sundar raj said:
2 decades ago
@Kiran
your answer is right only. But can you briefly explain how to find the value X from 2x2 + x - 3 = 0.
your answer is right only. But can you briefly explain how to find the value X from 2x2 + x - 3 = 0.
(1)
Priya said:
1 decade ago
Yes, please tell me if any short method is available.
(1)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers