find mean and median of first 20 composite number
Answers
The mean of first 20 composite numbers is 18.35, and the median of first 20 composite numbers is 19.
1) A composite number is a number which is divisible by a factor other than 1 and the number itself.
2) The first 20 composite numbers are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, and 32.
Note - 1 is neither prime nor composite.
3) Mean of first 20 composite number is the average of the 20 composite numbers.
Therefore, mean = (Sum of the numbers / 20) = (4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 + 20 + 21 + 22 + 24 + 25 + 26 + 27 + 28 + 30 + 32) / 20 = 367/20 = 18.35
4) To calculate the median, the composite numbers have to be arranged in the ascending order first. Here, the numbers are already arranged in ascending order.
5) Median = (Total number of values + 1) / 2
Therefore, median of 20 composite numbers = (20 + 1) / 2 = 21/2 = 10.5
Since 20 is an even number, the median will be the average of the 10th and the 11th composite numbers in the series.
6) The 10th number is 18, and the 11th number is 20. Therefore,
Median = (18 + 20) / 2 = 38/2 = 19.