Question

The distance between two stations a and b is 200 km. A train leaves a towards b at an average speed of 60 km/hr. After an hour, another train leaves b towards a at an average speed of 80 km/hr. The distance of the point where the two trains meet, from a is

Answer 1

Let time taken by train from A = t

Then time taken by train from B = t-1 (∵ it starts 1 hr later)

Distance traveled by train from A in time t= 60 × t = 60t

Distance traveled by train from B in time t-1= 80 ×(t-1)= 80(t-1)

Distance traveled by train from A + distance traveled by train from B = 200

60t+80(t-1)=200

60t+80t-80=200

140t=200+80

t=280/140

t=2 hrs.