If the mean of five observations x, x + 2, x + 4, x + 6 and x + 8 is 11, then the value of x is

Let L be the lower class boundary of a class in a frequency distribution and m be the midpoint of the class. Which one of the following is the upper class boundary of the class?

The mid-value of a class interval is 42 and the class size is 10. The lower and upper limits are

If the mean of x, x + 3, x + 5, x + 7, x + 10 is 9, the mean of the last three observation is