Question

The median of first ten prime numbers is
A. 9
B. 12
C. 15
D. 20

Answer 1

Hint: Write the first ten prime numbers either in ascending or in descending order. Then, choose the middle terms from the numbers. Since, the number of observations is even, we will have two middle terms. Take the average of both the middle terms to calculate the required median.

Complete step-by-step answer:
Prime numbers are the numbers that have only two factors, the number 1 and the number itself.
The first ten prime numbers are 2,3,5,7,11,13,17,19,23,29
We have to find the median of these numbers.
Median is also known as the middle value of the data, when the data is arranged in either ascending or descending order.
Since, there are 10 numbers, that is total observations are even, we will have 2 middle terms.
Here, we can observe that there are 2 middle numbers, 11 and 13.
We will take the average of the middle numbers to find the median of the median.
Hence, average of 11 and 13 is $\dfrac{{11 + 13}}{2} $
= $\dfrac{{24}}{2} $
= 12
Therefore, the median of the first ten prime numbers is 12.
Hence, option B is correct.

Note: Students often make mistakes in writing the prime numbers. All odd numbers are not prime numbers. For example, number 15 is an odd number but it has more than two factors, which are 1, 3, 5 and 15. Therefore it is not a prime number. Also, 1 is neither a prime nor a composite number.