The remainder when 321 is divided by 5 is

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The remainder when 3²¹ is divided by 5 is

1. 1
2. 2
3. 3
4. 4

Correct Option: C

As we know that ,
3¹ = 3; 3² = 9; 3³ = 27; 3⁴ = 81; 3⁵ = 243
i.e. unit’s digit is repeated after index 4.
Remainder after dividing 21 by 4 = 1
∴ Unit’s digit in the expansion of (3)²¹ = 3
∴ Remainder after dividing by 5 = 3