Average - Questions and Answers

21. The average age of three boys is 15 years. If their ages are in the ratio 3 : 5 : 7, the age of the youngest boy is :

22. The average score of a cricketer for 10 matches is 43.9 runs. If the average for the first six matches is 53, the average for the last four matches is :

23. The average consumption of petrol for a car for seven months is 110 litres and for next five months it is 86 litres. The average monthly consumption is :

24. The average of 30 results is 20 and the average of other 20 results is 30. What is the average of all the results?

25. Out of three numbers, the first is twice the second and is half of the third. If the average of the three numbers is 56, the three numbers in order are :