Question

point A and B are 80 km apart on a highway one car starts from A and another from B at the same time if the cars travel in the same direction at different speeds they meet in 8 hours if they travel towards Each Other they meet the meet in 1 hour 20 minutes what are the speed of the two cars​

Answer 1

Answer:

Let the speed of car at place A is x km/h and that of car at place B is y km/h

If they travel in same direction, they will meet after 7 hours, i.e. the difference of distance covered by them in 7 hours will be equal to distance b/w A and B.

As, distance = speed × time, and distance from A to B is 70 km

⇒ 7x - 7y = 70

⇒ x - y = 10

⇒ x = y + 10 eq.[1]

If they, travel in opposite direction, they will meet after 1 hour i.e. sum of distance travelled by both cars will be equal to the distance b/w A and B.

⇒ x + y = 70

Using eq.[1], we have

⇒ y + 10 + y = 70

⇒ 2y = 60

⇒ y = 30

Using this in eq.[1], we have

x = 30 + 10 = 40

Hence,

Speed of car at A = x = 40 km/h

Speed of car at B = y = 30

Answer 2

Solution:-

Let the speeds of the cars be x km/hr and y km/hr

Case 1:

the cars are going in the same direction

Relative speed = x - y

Distance = 100 km

time(t) = 100 / (x - y) = 5 hrs

x - y = 100 / 5=20

x – y = 20 ------------- (1)

Case 2:

the cars are going in the opposite direction

Relative speed = x + y

time(t) =100 / (x + y) = 1 hrs

x + y = 100 ------------- (2)

Solving the equations (1) and (2),

x = 60

y = 40

Hence the speeds of the cars are 60 km/hr and 40 km/hr.

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@GauravSaxena01