A batsman scored 87 runs in the 21st match in his career. His average of runs per match increased by 2. What was his average before the 21st match?

The average weight of 8 people is increased by 2 kg when a new person comes in place of the person who weighs 50 kg. What is the weight of the newcomer?

The average age of three boys is 15 years if their ages are in the ratio 3 : 5 : 7, what will be the age of the youngest boy?

In a year, the average expenditure of a family for the first 3 months, next 4 months and last 5 months is Rs 8400 per month, Rs 10080 per month, Rs 10608. Monthly and annual savings are Rs. 8640. If so, what is the average monthly income of this family?

The average of 8 numbers is 38.4. Out of these numbers, the average of 7 number is 39.2. The 8th numbers

The average of all the numbers between 6 and 50 which are divisible by 5 is

The average of 100 numbers is 44. The average of these 100 numbers and 4 other new numbers is 50. The average of the four new numbers will be

The mean of 9 observations is 16. One more observation is included and the new mean becomes 17. The 10th observation is