Arjun covers one-third of a certain distance at a speed of 45 km/h. He covers half of the remaining distance at a speed of 60 km/h and the rest of the distance at a speed of 90 km/h. What is his average speed for the entire journey?

Ramesh covers 56 part of the total distance by bus and the remaining 36 km by car. What is the total distance of his journey?

A person covers a distance of L km in 12 hours. If he increases his speed by 10 m/s, he covers the same distance in 8 hours. Which of the following statements is/are correct? I. The value of L is 760 km. II. The original speed of the person is 72 km/h.