Arithmetic MCQ 6 (Average of given numbers)
MCQ 6: The average of first ten prime numbers which are odd is____________?
a) 12.9 b) 13.8 c) 15.8 d) 17
Solution:
Prime numbers ( or primes) are the numbers which are divisible by themselves or by 1
They start from ;
2 , 3, 5, 7 , 11, 13, 17, 21, 23, 27, 31, 37 …………….and so on !
But we have been given the first ten odd PNs which are;
3, 5, 7 , 11, 13, 17, 21, 23, 27, 31
To find their average we use ;
\[ Average = \frac{Sum Of Terms}{Total Number Of Terms} \]
Here sum is;
3+5+7+11+13+17+21+23+27+31 =158
And total number of terms i-e total number of odd prime numbers is 10
so,
\[ Average = \frac{158}{10}=15.8 \]
i-e option c is correct
About Numbers
The average of the first ten primes which are odd is
are divisible by themselves only.
2 is the only even prime number.
The question is about first 10 PNs excluding 2.
Primes are all odd except 2 but all primes are not odd.
Odd numbers are divisible not by 2.
1 is a prime number,
all primes are infinite,
define prime number divisible by themselves.
2 is a prime number which is even,
primes are never-ending,
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