Mean of raw data and frequency distribution

The mean of 14, 10, 18, c, 21, 15, 14 is 15.

The sum of all the numbers is

If the mean of four numbers 4, 8, x and 12, is 10. How is the value of x calculated?

How is the mean of 2x, 3x, 4x and 3x calculated?

The frequency table below show the marks obtained by a class in a test.

How many students are in the class?

What is the formula for mean of a frequency distribution?

What is the calculation for mean?

What is the mean mark for the above distribution?

The mean height of 12 cricketers is 165 cm. Calculate the total height if a cricketer of height 176 cm leaves the team.

The mean mass of 15 persons is 53 kg. If one person of mass 69 kg joins the group how is the new mean calculated?

The mean mark of 25 students in a test is 73. Determine the mean mark if a student whose mark was 85 was absent from the test.