CBSE Class 10 Answered

We know that Speed = Distance/ Time

Now let say the speed of the train is x km/hr and speed of the bus is y km/hr.

According to the question, Roohi takes 4 hours if she travels 60 km by the train and rest by bus

4 = 60/x + 240/y

also, If she travels 100 km by train and rest by bus, she takes 4 hours and 10 minutes.

4 hours and 10 minutes = 4 + 1/6 = 25/6 hrs

Therefore, 25/6 = 100/x + 200/y

Now take 1/x =u and 1/y = v solve the two equations u and v

and then sunstitute to get x and y.