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:
209 comments Page 7 of 21.
Karthik said:
2 decades ago
(600/x)-600/(x+1/2)=200
(600/x)-600*2/(2x+1)=200
take LCM we will get
(600(2x+1)-600*2*x)/x*(2x+1)=200
600(2x+1)-600*2*x=200*x*(2x+1)
600(2x+1)-200*x*(2x+1)=600*2*x
i think now it ll b easy to simply
(600/x)-600*2/(2x+1)=200
take LCM we will get
(600(2x+1)-600*2*x)/x*(2x+1)=200
600(2x+1)-600*2*x=200*x*(2x+1)
600(2x+1)-200*x*(2x+1)=600*2*x
i think now it ll b easy to simply
Nagaraju said:
1 decade ago
What a problem it is !
Firstly, I think that want to solve with the help of Relative formula is there na. 2xy/x+y but. It not suitable. So, thought another way and got the answer. Simply a good problem.
Firstly, I think that want to solve with the help of Relative formula is there na. 2xy/x+y but. It not suitable. So, thought another way and got the answer. Simply a good problem.
Simi said:
1 decade ago
@ISHAN. The speed of the car is 70 km/hr.
Solve the following eqquation:
t-1 = 420/x+10 km/hr.
= 420/x - 420/ x + 10 = t-t-1.
= 420 x + 4200- 420 x = t-t-1.
= 4200 = -1.
= 4200 / 60 (mins)= 70 kms/hr.
Solve the following eqquation:
t-1 = 420/x+10 km/hr.
= 420/x - 420/ x + 10 = t-t-1.
= 420 x + 4200- 420 x = t-t-1.
= 4200 = -1.
= 4200 / 60 (mins)= 70 kms/hr.
Miithun A said:
1 month ago
Given:
Distance = 600 km.
Speed reduced by = 200 km/hr.
Time increased by = 0.5 hr.
Let us assume;
Original time = 600/600 = 1 hr.
Reduced speed = 600 − 200 = 400 km/hr.
New time = 600/400 = 1.5 hr.
Distance = 600 km.
Speed reduced by = 200 km/hr.
Time increased by = 0.5 hr.
Let us assume;
Original time = 600/600 = 1 hr.
Reduced speed = 600 − 200 = 400 km/hr.
New time = 600/400 = 1.5 hr.
(2)
Ravi said:
5 years ago
S=D/T(30 min increased).
200 = 600/(x+30).
x+30 = 600/200,
x+30 = 3,
x = 27.
Time is always positive.
So, time increses by 30=x+30.
= 27 + 30 = 57 = 1hr.
200 = 600/(x+30).
x+30 = 600/200,
x+30 = 3,
x = 27.
Time is always positive.
So, time increses by 30=x+30.
= 27 + 30 = 57 = 1hr.
(24)
Manikanta said:
1 decade ago
I have a doubt in the question its average speed for the trip was reduced by 200 km/hr is given but trip means both up and down so that its 1200 kms but in the answer only 600 km is taken.
Sonali said:
9 years ago
@Patreppa.
((2x+1)600-1200x)/x(2x+1)=200
(1200x+600-1200X)=200*x(2x+1)
600=200(2x^2+x)
600=400x^2+200x
400x^2+200x-600=0
Divide by 200 then(just for simplification).
2x^2 + x - 3 = 0.
((2x+1)600-1200x)/x(2x+1)=200
(1200x+600-1200X)=200*x(2x+1)
600=200(2x^2+x)
600=400x^2+200x
400x^2+200x-600=0
Divide by 200 then(just for simplification).
2x^2 + x - 3 = 0.
Harika said:
5 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)
Circle said:
2 years ago
The speed of the second train =400/4 = 100km/h.
Distance is same in both cases:
Then,
The ratio of speed = reverse ratio of time
7/8 = 8/7.
Speed of first train = 100/8/7= 87.5km/h.
Distance is same in both cases:
Then,
The ratio of speed = reverse ratio of time
7/8 = 8/7.
Speed of first train = 100/8/7= 87.5km/h.
(16)
Suchitra said:
1 decade ago
@Mallikarjun.
Why it can't be like?
400 km. > 30 min.
600 km. > ?
Why are you taking 200? 200 is the speed reduced?
So shouldn't you subtract from 600 and take it as 400.
Why it can't be like?
400 km. > 30 min.
600 km. > ?
Why are you taking 200? 200 is the speed reduced?
So shouldn't you subtract from 600 and take it as 400.
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