If M is a positive integer such that average (arithmetic mean) of 31, 33, M, 36, and 37 lies between 40 and 43 (both inclusive). What is the number of possible values of M?

A certain list of 200 test scores has an average (arithmetic mean) of 85 and a standard deviation of d, where d is positive. Which of the following two test scores, when added to the list, must result in a list of 202 test scores with a standard deviation less than d ?

There are 16 teams in a tournament. If during the first round, each team plays every other team exactly once, how many games will be played in the first round?

Last year members of a certain professional organization for teachers consisted of teachers from 49 different school districts, with an average (arithmetic mean) of 9.8 schools per district. Last year the average number of teachers at these schools who were members of the organization was 22. Which of the following is closest to the total number of members of the organization last year?

x, 0, 13, −7, y, 7

In the list of numbers above, if x < y and the median of the numbers in the list is 8, what is the value of x ?

The harmonic mean of n numbers is the reciprocal of the arithmetic mean of their reciprocals. What is the harmonic mean of 2, 4, 6, and 12 ?

5 collectors have some rare collection, then comes the 6^th collector with 50 pieces of collection, and then the average piece of collection is 5 more than the average before. Then comes the 7^th collector with some collection, and the average is 5 more than the average of the first 6 collectors. How many pieces of collection does the 7^th collector have?

Set A consists of integers {3, -8, Y, 19, -6} and Set B consists of integers {K, -3, 0, 16, -5, 9}. Number L represents the median of Set A, number M represents the mode of set B, and number Z = L^m. If Y is an integer greater than 21, for what value of K will Z be a divisor of 26?

The arithmetic mean of the 5 consecutive integers starting with 's' is 'a'. What is the arithmetic mean of 9 consecutive integers that start with s + 2?

The arithmetic mean of the nine numbers in the set {9, 99, 999, 9999, ..., 999999999} is a 9-digit number M, all of whose digits are distinct. The number M does not contain the digit