Aptitude - Time and Distance - Discussion

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.

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.

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.

How 600/x-600/x+1/2=200?

Why we take the difference and why it equal to 200?

Can anyone explain 1st step, I'm not understanding.

How 600/x-600/x+2=200?

Please explain this step.

Hey guys!

Actually x=3/2 is the correct answer.
if new time = 1.5 hrs(i.e 3/2 hrs)
then original time=1.5-0.5(i.e 30 minutes)
=1 hr.

Then original speed = 600 kmph (since 600 km in an hr)
new speed = 600-200
= 400 kmph.

New time = 600/400
= 1.5 hrs (fits correctly with x=1.5 i.e our initial assumption).
Now,
x=1
original time =30 minutes= 0.5 hr
original speed = 600 kmph * 05 hr
= 1200 kmph
new speed = 1200-200
= 1000 kmph.

new time = 600/1000
= 36 minutes.

Since x=30 minutes; x is not equal new time.
so conclusion:- time =1.5 hrs (answer choices are incorrect).

Because converting 30 min into an hour because everything is given in hour so 30 min/60 to convert into hour so here it comes 1/2.

@All.

The Original duration or the duration it has taken? Confused by the answer.

I think original duration is 1 hour but it has taken 30 mins more due to bad weather. Am I right?

Please anyone explain me.

Thank you @Kiran.