Question

Find the average of all prime numbers between 30 and 50
A.40
B.42
C.39
D.39.8

Answer 1

Hint: As we know, Prime numbers are the numbers which are only divisible by 1 and itself for example, 1, 2, 3, 5, 7 etc. So, firstly we have to find all the prime numbers between 30 and 50. Then we have to find their average and to find the average we have to add all the prime numbers between 30 and 50 and then dividing them by the number of prime numbers between 30 and 50. Average = sum of prime numbers (between 30 and 50) / total number of prime numbers (between 30 and 50).

Complete step-by-step answer:
At first, we have to find all the prime numbers between 30 and 50
Now, the prime numbers between 30 and 50 are 31, 37, 41, 43 and 47
Now, the total number of prime numbers between 30 and 50 are 5
We know that,
 Average = sum of prime numbers (between 30 and 50) / total number of prime numbers (between 30 and 50).
Substituting the values in above formula,
Average will be
 $
  = \dfrac{{31 + 37 + 41 + 43 + 47}}{5} \\
   = \dfrac{{199}}{5} \\
   = 39.8 \\
 $
 Therefore Average is $39.8$
Hence, the answer is option D.

Note: We know that prime numbers are the numbers which are only divisible by 1 and itself, so find them always be careful and take your time to analyze every number to check whether it is prime number or not.