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 19 of 21.
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)
Yogi said:
4 years ago
Simple,
Here is a trick, for such question, always break distance in its multiple,
For e,g.
600km = 300kmph x 2 hour.
Or
600km = 600kmph x1 hour
So we can see for 300kmph it takes 2 hours and for 600kmph it takes 1 hour.
And that's the answer.
Here is a trick, for such question, always break distance in its multiple,
For e,g.
600km = 300kmph x 2 hour.
Or
600km = 600kmph x1 hour
So we can see for 300kmph it takes 2 hours and for 600kmph it takes 1 hour.
And that's the answer.
(10)
Ravi said:
4 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)
Navin said:
4 years ago
@Saravanakgopi.
Thanks for simplifying the answer in detail.
Thanks for simplifying the answer in detail.
Tony said:
4 years ago
Anyone, please explain from the 2nd Step.
Nitu said:
4 years ago
Thank you everyone for explaining.
(1)
Nitu said:
4 years ago
600/x - 1200/2x+1 = 200.
Lcm is
You get (2x+1)(600) - 1200x = 200(2x^2 +x).
1200x+600-1200x = 200(2x^2 +x),
600/200(2x^2+1),
3/(2x^2+x),
2x^2+x = 3.
X = 1.
Lcm is
You get (2x+1)(600) - 1200x = 200(2x^2 +x).
1200x+600-1200x = 200(2x^2 +x),
600/200(2x^2+1),
3/(2x^2+x),
2x^2+x = 3.
X = 1.
(8)
ANKIT said:
4 years ago
Thanks @Kiran.
(3)
Yash Soni said:
3 years ago
Can we take the difference of time instead of speed? Please anyone explain me.
Varun said:
3 years ago
@Saravanakgopi.
It's wrong.
When you got 200 (x+30) =600. Then the next step would be 200x=600-6000. The result you get is negative.
So the final answer you get if you follow that method would be x= -27. So when you add it with increased time then -27+30 Which is 3.
It's wrong.
When you got 200 (x+30) =600. Then the next step would be 200x=600-6000. The result you get is negative.
So the final answer you get if you follow that method would be x= -27. So when you add it with increased time then -27+30 Which is 3.
(6)
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