The percentage of marks obtained by 12 students of a class in mathematics are

64, 36, 47, 23, 0, 19, 81, 93, 72, 35, 3, 1.

Find the mean percentage of marks.

The following are the number of books issued in a school library during a week:

105, 216, 322, 167, 273, 405 and 346.

Find the average number of books issued per day.

The daily minimum temperature recorded (in degree F) at a place during a week was as under:

Find the mean temperature.

If the arithmetic mean of 7, 9, 11, 13, x, 21 is 13, find the value of x.

The mean of 24 numbers is 35. If 3 is added to each number, what will be the new mean?