Statistics Mean Mock Tests

In a class, the average score of 12 boys is 70 and the average score of 8 girls is 80. What is the average score of the entire class?

The mean of 10, 20, 30, and x is 25. What is x?

The average of 4, 8, and x is 8. What is the value of x?

The mean of 5, 10, 15, 20, and x is 14. What is the value of x?

The average age of 25 employees in a department is 35 years. When the manager's age is included, the average increases by 2 years. What is the manager's age?

The average score of 8 students on a test is 75. If the teacher's score is included, the average increases by 2 points. What is the teacher's score?