The question is, Is n odd?
The given question is a "be verb" question. The answer to such questions will be yes or no.
Data is sufficient only if we can answer the question with a definite yes or a definite no.
From the question stem, 20 < n < 80.
Let us evaluate the statements.
Statement-1: Both digits of n are prime numbers.
Let us try with examples to establish an argument and then work on a counter-argument to contradict the earlier established argument.
Example: Assume n to be 23. Here both 2,3 are prime and n is odd. So the answer to the question is YES.
Counter-Example: Assume n to be 32. Here 3,2 are prime and n is even. So the answer to the question is NO.
Because a counter-example exists, we cannot answer the question with a definite yes or a definite no.
So, statement-1 alone is not sufficient.
Choice-A and Choice-D can be eliminated.
Statement-2: The sum of n’s two digits is a prime number.
We can use the same examples used above.
Example: Assume n to be 23. Here the sum of 2 and 3 is prime and n is odd. So the answer to the question is YES.
Counter-Example: Assume n to be 32. Here the sum of 3 and 2 is prime and n is even. So the answer to the question is NO.
Because a counter-example exists, we cannot answer the question with a definite yes or a definite no.
So, statement-2 alone is not sufficient.
Choice-B can be eliminated.
Combining the statements, we have both digits of n as prime numbers and the sum of n’s two digits is a prime number.
We can again use the same examples we have used above.
Example: Assume n to be 23. Here 2, 3 are prime, the sum of 2, and 3 is prime and n is odd. So the answer to the question is YES.
Counter-Example: Assume n to be 32. Here 3, 2 are prime, the sum of 3, and 2 is prime and n is even. So the answer to the question is NO.
Because a counter-example exists, we cannot answer the question with a definite yes or a definite no.
So, Statement-1 & 2 together are not sufficient.
Choice-C can be eliminated.
So, the answer is Choice-E.
Statements (1) and (2) TOGETHER are not sufficient.