Question

Four options have been given out of which three are alike in some manner, while one is different. Choose the odd one.
1. 429
2. 336
3. 257
4. 259

Answer 1

Correct Answer - Option 3 : 257

Given: 429, 336, 257, 259

All the numbers except option (3), the given number is exactly divisible by any number. 

Here we see only 257 is the prime number.

Option 1: 429 → It is divisible by 3.

Option 2: 336 → It is divisible by 3.

Option 4: 259 → It is divisible by 7.

Hence, the correct answer is 257.

• The priority will always be the prime number in the exams.
• There are some standard rules which need to be followed while selecting the priority.
• priority lists to be followed in exams according to their preferences are:

1. Prime number.
2. Square.
3. Cube.
4. Multiplication and divisions
5. Addition and subtraction.

• A prime number can be divided, without a remainder, only by itself and by 1.
• Some facts about the Prime numbers:

1. The only even prime number is 2. All other even numbers can be divided by 2.
2. If the sum of a number's digits is a multiple of 3, that number can be divided by 3.
3. No prime number greater than 5 ends in a 5. Any number greater than 5 that ends in a 5 can be divided by 5.
4. Zero and 1 are not considered prime numbers.
5. Except for 0 and 1, a number is either a prime number or a composite number. A composite number is defined as any number, greater than 1, that is not prime.