Question

a man travels 600km partly by train and partly by car. it takes 8hr 40 min if he travel 320 km by train and rest by car it would takes 30 min more if he travels 200km by train and rest by car. what is the speed of the car?

Answer 1

Let speed of train be x
Let speed of care be y
We know that Distance = Speed * Time
ATQ :-
320/x + (600-320)/y = 8 + 40/60 hours = 8 + 2/3 hours..............................................(1)
200/x + (600-200)/y = 8 + 40/60 + 30/60 = 8 + 2/3 + 1/2...........................................(2)
I have just used the formula Time = Distance/Speed to write speed of train and car individually.
Writing (1) and (2) as linear equations by putting 1/x=a and 1/y=b..............................(3)
320a + 280b = 8 +2/3
200a + 400b = 8 + 2/3 + 1/2
Thus, solving the above equations, we get a = 1/80 and b=1/60
Now, x = 80 and y = 60 ................................................................................using (3)
So, speed of train is 80 kmph and speed of car is 60 kmph.
Good if understood, if not then please comment :-)
All the Best !     :-)

Answer 2

Hope it helps you................