Exercise 1

A pupils marks were wrongly entered as 83 instead of 63. Due to that average marks for the class got increased by half. The number of pupils in the class is

While calculating the average of a batsman as 36 in 100 matches that he played, one of the scores 90 was incorrectly noted as 40. The percentage error is

The average age of seven boys sitting in row facing North is 26 years. If the averages age of the first three boys is 19 years and the averages age of the last three boys is 32 years, what is the age of the boy who is sitting in the middle of the row?

The average of five numbers is 306.4 the average of the first two numbers is 431 and the average of the last two numbers is 214.5. What is the third number?

The average marks obtained by 22 candidates in an examination are 45. The average marks of the first ten are 55 and that of the last eleven are 40. The number of marks obtained by the 11^th candidate is

The average of 11 numbers is 10.9 if the average of the first six numbers is 10.5 and that of the last six numbers is 11.4, then the middle number is:

The average temperature for the first four days of a week is and that of the last four days is . if the average temperature for the whole week is , then the temperature on the fourth day is

The average weight of three boys A, B and C iskg, while the average weight of three boys B, D and E is 53 kg. What is the average weight of A, B, C, D and E?

The average of the ages of Summit, Krishna and Rishabh is 43 and the average of the ages of Sumit, Rishabh and Rohit is 49. If Rohit is 54 years old, what is Krishna’s age?

The mean temperature of Monday to Wednesday wasand Tuesday to Thursday was . If the temperature on Thursday was that of Monday, the temperature on Thursday was