A takes 3 hours more than B to walk 'd' km. If A doubles his speed, then he can make it in 1 hour less than B. How much time (in hours) does A require to walk 'd' km?

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.