Question : A man covers a total distance of 100 kilometres on a bicycle. For the first 2 hours, the speed was 20 km/hr and for the rest of the journey, it came down to 10 km/hr. The average speed will be:

Question : What is the average thickness of the continental crust of the Earth?

Question : A man travels $\frac{3}{4}$th of the distance of his journey by bus, $\frac{1}{6}$th by rickshaw and the remaining 2 km on foot. The total distance travelled by the man is:

Question : Directions: The distance between the two cities is 30 km. A man goes at a speed of 30 km per hour and returns at 20 km per hour. What is his average speed?

Question : The average of 8 numbers is 18. If one of the numbers is excluded, the average becomes 20. Find the excluded number.