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:
206 comments Page 18 of 21.
Abhishek rohan said:
8 years ago
In question avg speed given:
The avg speed= total distance/total time elapsed
So according to question the equation becomes:
1200/2t - 200 =1200/(2t+1/2).
After solving,
4t^2+t-3=0,
(4t+3)(t-1)=0,
so t=1;(taking positive value).
The avg speed= total distance/total time elapsed
So according to question the equation becomes:
1200/2t - 200 =1200/(2t+1/2).
After solving,
4t^2+t-3=0,
(4t+3)(t-1)=0,
so t=1;(taking positive value).
Lalit sharma said:
8 years ago
Another simple way of doing this is solve by;
600/(x-200)- 600/(x) = 1/2.
we get x= 600km/hr.
Time=distance/speed = 600/600 = 1hr.
600/(x-200)- 600/(x) = 1/2.
we get x= 600km/hr.
Time=distance/speed = 600/600 = 1hr.
Patreppa said:
8 years ago
Yesh, I understood till,
(600/x) - (1200/(2x+1)) = 200.
Please, can anybody simplify this, only let me know, please.
(600/x) - (1200/(2x+1)) = 200.
Please, can anybody simplify this, only let me know, please.
Sonali said:
8 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.
Kannan said:
8 years ago
Distance=600km
Speed=200km
Time=x+30mins
So we have to the time duration,
Time = Distance/speed.
x+30=600/200,
x+30=3,
x=3-30,
x=27mins(neglect the negative),
x=27+30min,
x=57 mins(Almost 1hr),
Ans x=1hr.
Speed=200km
Time=x+30mins
So we have to the time duration,
Time = Distance/speed.
x+30=600/200,
x+30=3,
x=3-30,
x=27mins(neglect the negative),
x=27+30min,
x=57 mins(Almost 1hr),
Ans x=1hr.
Magnesh said:
8 years ago
Let the time be x.
Total speed(Dis/time) - actual speed due to weather(dis/time) = reduced speed.
600/x - 600/ x+(1/2) = 200.
Here actual speed is less because of weather condition, which means it has taken MORE TIME which is 1/2 hour or 30 min.
Solve answer you get an answer as 1 hr.
Total speed(Dis/time) - actual speed due to weather(dis/time) = reduced speed.
600/x - 600/ x+(1/2) = 200.
Here actual speed is less because of weather condition, which means it has taken MORE TIME which is 1/2 hour or 30 min.
Solve answer you get an answer as 1 hr.
Adil said:
8 years ago
Thanks @Kiran.
Maulik Gajjar said:
8 years ago
Change in in speed i.e speed reduced by 200 kmph then change in time is 30 mnts.
If speed reduce to zero i.e by 600kmph. Time taken will be 90 mnts.
As mentioned in the question, Flight took 30 months more.
To find the original time of flight, 90 -30 = 60 months, i.e 1 hour.
If speed reduce to zero i.e by 600kmph. Time taken will be 90 mnts.
As mentioned in the question, Flight took 30 months more.
To find the original time of flight, 90 -30 = 60 months, i.e 1 hour.
Sneha said:
8 years ago
600(2x+1)-1200x=200x(2x+1).
1200x+600-1200x=400x^2+200x.
600=400x^2+200x,
300=200x^2+100,
3=2x^2+x,
2x^2+x-3=0.
1200x+600-1200x=400x^2+200x.
600=400x^2+200x,
300=200x^2+100,
3=2x^2+x,
2x^2+x-3=0.
Chetna said:
8 years ago
30 min =1/2 hr.
Now I take time T in hr.
According to the question..... Distance is same so,
Distance of Normal flight = Distance due to bad weather (reduce by 200 kmph).
We know, distance = time * speed.
T*600 = ( 600-200) (T + 1/2) ..... (600-200 bcz speed is reduce by 200 kmph).
600T = 400T +200.
T= 1 hr.
Now I take time T in hr.
According to the question..... Distance is same so,
Distance of Normal flight = Distance due to bad weather (reduce by 200 kmph).
We know, distance = time * speed.
T*600 = ( 600-200) (T + 1/2) ..... (600-200 bcz speed is reduce by 200 kmph).
600T = 400T +200.
T= 1 hr.
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