Question

point A and B are 70 KM apart on a highway A car starts from A and another car starts from b simultaneously if they travel in the same Direction they meet in 9 hours but if they travel towards Each Other they meet in 1 hour find the speed of the two cars ​

Answer 1

A.____________.B

Distance between A & B is 70km.

←A & ← B both travel in same direction.

but their speed is not the same. So they both meet after 7 hours.

let the speed of A be x and B be y.

if they travel towards each other →← they meet in 1 hour.

when they are moving in same direction ,the speed is x-y.

when they are moving towards each other,the speed is x+y.

Distance = 70km

7(x-y)=70

x-y=10---›(i)

similarly

1(x+y)=70

x+y=70---›(ii)

Solving (i) & (ii)

x+y=70

x -y=10

_____

2x=80.

x=80/2=40 Km/ hr.

substitute x in x+y=70

so,40+y=70;y=30 km/hr.

The speed of Car A is 40km/hr.

The speed of Car B is 30 km/hr.

Thank you.

Answer 2

First Let's take them opposing each other .

Let the first car travel x

then second will travel 70-x

so x=v1t+1/at^2

and 70-x=-v2t+1/2at^t

Here t=1hour

Now that will give you an equation in v1 and V2

Apply Similarly on The case where they are in same direction

If They meet at a distance of y from point B

then first car travels

70+y=v1t+1/2at^2

and second

y=v2t+1/at^2

here t=9hours

again solve to get an equation in v1 and v2

so you have two equations and two variables that is v1 and v2

Use elimination to get v1 ,v2