Question

Which of the following will end with digit 1?

• A. ${12}^2$
• B. ${25}^2$
• C. ${29}^2$
• D. ${30}^2$

Answer 1

The correct option is C ${29}^2$

If the unit digit of square of a number is 1 then,
unit digit of number must be 1 or 9.
And In option 'c' unit digit of the number 29 is 9. So its square ends with digit 1.