One third of a certain journey is covered at the speed of 40 km/hr, one fourth at the speed of 25 km/hr and the rest at the speed of 50 km/hr. what will be the average speed(in km/hr) for the whole journey?

A person travels 600 km by train at 80 km/hr 800 km by ship at 400 km/ hr and 100 km by car at 50 km/hr. What is the average speed for the entire distance? 

Vipin swims in a 72 meter long pond. He travels 144 meters in one minute by swimming from one end to the other and coming back the same way, find his average speed.

A car running at 7/11 of its own speed reached a place in 22 hrs. How much time could be saved if the car would run at its own speed?

A bus can cover a distance of 420 km in 7 hours. How much will the speed have to be increased to cover this distance in 6 hours?

A man starts from his house and travelling at 30 km/h, he reaches his office late by 10 minute, and travelling at 24 km/h, he reaches his office late by 18 minutes. The distance (in km) from his house to his office is:

A 275 m long train crosses a platform of equal length in 33 s. What is the speed of the train in km/h? 

There are three athletes A, B and C at a same point. A starts running from a point at a speed of 40 m/min. After 5 minutes, B starts running after A with a speed of 50 m/min. Simultaneously, C also starts running after A at 60 m/min. What distance has C covered (in m) when he catches A?