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 17 of 21.
Tanshi said:
8 years ago
600/x = 1200/2x+1+200.
600/x = 1200+(2x+1)(200)/2x+1 (for whole 2x+1).
600/x = 1200+400x+200/2x+1 (for whole 2x+1).
2x+1(600) = x(1200+400x+200).
1200x+600 = 1200x+400x^2+200x (cancel 1200x on bboth sides).
So 400x^2+200x-600.
600/x = 1200+(2x+1)(200)/2x+1 (for whole 2x+1).
600/x = 1200+400x+200/2x+1 (for whole 2x+1).
2x+1(600) = x(1200+400x+200).
1200x+600 = 1200x+400x^2+200x (cancel 1200x on bboth sides).
So 400x^2+200x-600.
Srinu said:
8 years ago
Why should we take the diff between the velocity's as reduced speed?
Please briefly explain any one.
Please briefly explain any one.
Aditya said:
8 years ago
Does anybody think the 1/2 should be added to make the answer to 1.5hr?
Priya said:
8 years ago
2x^2 - 2x + 3x - 3 = 0. How we get it? Explain.
Tejadeep said:
8 years ago
Why we have to consider the difference of two distance can anyone explain? please.
Vineet said:
8 years ago
Hi, Can anyone tel that how to calculate speed and what is the final answer?
Sanju said:
8 years ago
Hi, in question they mentioned.
d=600km , s=200kmph , t=30min.
Let duration of flight = x.
wkt SPEED=DISTANCE/TIME (s=d/t).
200 = 600/x - 600/x+(30/60).
200 = 600/x - 600*2/2x+1.
By solving this we get,
2x^2+2x-x = 0,
x=1.
d=600km , s=200kmph , t=30min.
Let duration of flight = x.
wkt SPEED=DISTANCE/TIME (s=d/t).
200 = 600/x - 600/x+(30/60).
200 = 600/x - 600*2/2x+1.
By solving this we get,
2x^2+2x-x = 0,
x=1.
Ajit said:
8 years ago
Thanks for your valuable explanation @Bhavana.
Robin said:
8 years ago
I solve this problem like this
First, I check the facts given:
Distance = 600km.
Original speed = we don't know,
New speed = we don't know,
The Relation between new and original speed = new speed is 200km/h slower to original speed so the diff in speed is 200km/h.
Original time = we don't know,
New time = we don't know,
Relation between new and original Time = new time is 30minutes more than original time so the diff in time is an hour.
Now, I need two separate numbers with the diff of 200 and should be able to divide 600 with a diff of .5 (means) and the numbers are 600 and 400.
600/600 = 1 (original speed 600km/h and it takes 1 hour to reach).
600/400 = 1.5 (new speed 400km/h and it takes 1 hour 30 min to reach).
First, I check the facts given:
Distance = 600km.
Original speed = we don't know,
New speed = we don't know,
The Relation between new and original speed = new speed is 200km/h slower to original speed so the diff in speed is 200km/h.
Original time = we don't know,
New time = we don't know,
Relation between new and original Time = new time is 30minutes more than original time so the diff in time is an hour.
Now, I need two separate numbers with the diff of 200 and should be able to divide 600 with a diff of .5 (means) and the numbers are 600 and 400.
600/600 = 1 (original speed 600km/h and it takes 1 hour to reach).
600/400 = 1.5 (new speed 400km/h and it takes 1 hour 30 min to reach).
Murad Hossain said:
8 years ago
Suppose,
Duration = x hour.
600-200 = 400,
ATq,
x/400 - x/600 = 1/2,
2x = 1200,
x = 600,
So,
duration = 600/600 = 1 hour.
Duration = x hour.
600-200 = 400,
ATq,
x/400 - x/600 = 1/2,
2x = 1200,
x = 600,
So,
duration = 600/600 = 1 hour.
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