Question

What will be the remainder when 19^100 is divided by 20 ?​

Answer 1

19,20 are co-primes. So Euler's Theorem can be easily applied to. So according to Euler's Theorem, 19^100=19^4 (mod 20)=19*19*19*19=(-1)(-1)(-1)(-1)=1 (mod 20 )

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