Question

Question 10 (b)

Express the given number as the sum of three odd primes:
31

Answer 1

To obtain an odd number like 31, the possible combination are : odd + odd + odd = odd
even + even + odd = odd

Our second case fails because we only have 2 as an even prime number.

So, the only case is : odd + odd + odd = odd

Clearly, 3 + 11 + 17 = 31
Here 3, 11, and 17 are odd prime numbers.