Question

There are 4 numbers given below. 3 of them are similar and can be classified into a group. Which of these numbers forms a group?
1) 121
2) 169
3) 289
4) 441

• A. 1, 2 and 3
• B. 1, 2 and 4
• C. 1, 3 and 4
• D. 2, 3 and 4

Answer 1

The Correct Option is A

The numbers 121, 169, and 289 are perfect squares of integers:

• 121 = 11²
• 169 = 13²
• 289 = 17²

All of these numbers are squares of prime numbers. However, 441 is not a square of a prime number, as 441 = 21², where 21 is not a prime number. Therefore, the numbers 121, 169, and 289 form a group.

Conclusion: Thus, the correct answer is (A) 1, 2, and 3