Chapter I : Linear Equations in two variables in two variables

Example 19. Two places A and B are 120 km apart from each other on a highway. A car starts from A B and another from B at the same time. If they move in the same direction, they meet in 6 hours and if they move in opposite directions, they meet in 1 hour and 12 minutes. Find the speeds of the cars.

Solution: - Let the speed of car at A be X km/h and speed of car at B be y km/h

Distance covered by car at A in 6 hours = 6x

and distance covered by car at B in 6 hours = 6y

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

Adding (1) and (2) we get

2x = 120

x = 60

Putting x = 60 in (2) we get y = 40

Speeds of car are 60 km/h & 40 km/h.