1. A motorist covered the first 20 km of his journey in 30 minutes and the remaining 29 km in 40 minutes. His average speed in km/hr is:

2. The mean of 19 observations is 4. If one more observation of 24 is added to the data, the new mean will be:

3. A student bought 4 books for Rs. 120 from one book shop and 6 books for Rs. 150 from another. The average price (in rupees), he paid per book was:

4. The average of the price per kg. of rice at 10 different places was Rs. 4.85. After a week, the price per kg. was increased by 20 paise at 3 places and decreased by 10 paise at one place. The new average of price per kg is:

5. The average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that one weight was misread as 78 kg instead of the correct one of 87 kg. The correct average weight is:

6. A class has 20 boys and 30 girls. The average age of boys is 11 years and that of girls is 12 years. What is the average age of the whole class

7. Find the average of the following set of scores 253, 124, 255, 534, 836, 375, 101, 443, 760

8. What will be the average of even numbers between 11 to 63?

9. Find average of all prime numbers between 60 and 90.

10. Average age of 5 boys is 16 yr, of which that of 4 boys is 16 yr 3 months. The age of the 5th boy is

11. The average age of 30 girls is 13 yr. The average of first 18 girls is 15 yr. Find out the average age of remaining 12 girls?

12. The average of 13 results is 60. If the average of first 7 results is 59 and that of last 7 results is 61, what will be the seventh result?

13. The average of nine numbers is 50. The average of the first five numbers is 54 and that of the last three numbers is 52. Then, the sixth number is?

14. The average age of 30 women decreases by 3 months if a new person Neha is included in place of a 25 yr old woman. Calculate the age of Neha?

15. The average salary per head of all workers of an institution is Rs. 60. The average salary per head of 12 officers is Rs. 400. The average salary per head of the rest is Rs. 56. Then, the total number of workers in the institution is?

16. A cricketer scored some runs in his continuous 9 innings. He scored 100 runs in his 10th innings and this increased his average by 8 runs. What was the average of his runs at the end of 10th innings?

17. The average age of three boys is 15 yr. If the ratio of their ages is 3:5:7, what is the age of the oldest boy?

18. Nine friends have a dinner in a hotel. Eight of them spent Rs. 12 each on their meals and the ninth spent Rs. 16 more than the average expenditure of all the nine. Find out the total money spent by them?

19. The average of certain first consecutive even number is 101. Find their sum?

20. The average of certain first consecutive natural numbers is 20.5. Find their sum.