What will be the average of all the prime numbers before 19?
1). 8.28
2). 11.5
3). 5.34
4). 9.63
Prime numbers before 19 = 17, 13, 11, 7, 5, 3, 2
We know, Average = sum of all the number/total number
∴ Average = (17 + 13 + 11 + 7 + 5 + 3 + 2)/7 = 58/7 = 8.2810. What is the average of all natural numbers from 21 to 39?