Aptitude - Time and Distance - Discussion

Hi, Can anyone tel that how to calculate speed and what is the final answer?

Why we have to consider the difference of two distance can anyone explain? please.

2x^2 - 2x + 3x - 3 = 0. How we get it? Explain.

Does anybody think the 1/2 should be added to make the answer to 1.5hr?

Why should we take the diff between the velocity's as reduced speed?

Please briefly explain any one.

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.

Assume the normal time of flight was X.
Due to bad weather it was X+30 convert it into hours it would be X+ 1/2.
Normal speed of flight be S.
Due to bad weather, it was S-200.

First equation would be S = 600/X,
Second one would be S-200= 600/X+ 1/2.
Solve them equate Find the value of X by Equating in terms of X to each other
600/X=(1200/ 2X+1 )+ 200.

I have one doubt, due to bad weather the time increased by 30 min then we should add 30 min in x ie (x+30/60) or not?

Please help me.

distance = 600km, speed x kmph.

t = 600/x-----Actual time taken by journey.

t + 30 = 600/x - 200------> this due to reduce speed, x-200, 200kmph speed reduce from actual speed.
t = (600/x-200) - 30.

600/x = (600/x-200)-30/60------30min convert to hrs
600/x = (600/x - 200)-1/2,
600/x - 200 - 600/x = 1/2,
[600x - (x - 200)600]/x(x - 200) = 1/2,
x^2-200x - 240000 = 0,
x^2-600x + 400x - 240000 = 0,
x(x-600) + 400(x-600) = 0,
x-600 = 0,&x + 400 = 0 +ve values only consider.

x = 600kmph.
Actual journey time = 600/600 = 1hr.

@Babita.

Why are we taking 600-6000=200?

Can anyone give me the explanation?