Choose or find the odd number pair. (23-29), (19-25), (13-17), (3-5). A. 23 - 29 B. 19 - 25 C. 13 - 17 D. 3 - 5
Hint: For solving this question you should know about odd numbers and prime numbers. In this problem we will first find the odd number pair and then we will see if there are any prime numbers in the pair or not. If both the numbers of a pair are prime, then we will leave that and then apply the same on the other pairs.
Complete step-by-step solution: According to the question it is asked of us to find the pair of an odd number from (23 - 29), (19 - 25), (13 - 17), (3 - 5). So, if we want to solve this problem, then in the given problem first we will find the odd number pairs and then we will check if there prime numbers in the pair or not available any prime numbers in the pair. If both numbers of a pair are prime numbers, then we will leave that pair and we check the next pair with the same condition. And finally we will get the answer. So, if we see the pair (23 - 29). Then here both 23 and 29 are the prime numbers. If we check the pair (19 - 25), then 19 is the prime number but 25 is only an odd number, that is not prime. If we check the pair (13 - 17), here both are prime numbers. And if we check (3 - 5), then both 3 and 5 are prime numbers. So, the correct option is B.
Note: While solving these types of questions you have to keep in mind that all the prime numbers are odd numbers but all odd numbers are not prime numbers. So, during checking the prime and odd, check them carefully for both conditions. And many even numbers will be prime except 2.