Question

Find the remainder when 7^21+7^22+7^23+7^24 is divided by 25:-

a)0
b)2
c)4
d)6

Thank You!!

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Answer 1

Answer:

7^21(1+7+7^2 +7^3) =7^21(1+7+49+343)

=7^2 (400)

=7^21(25*16)

If you divide the above number with 25 the remainder is 0

Answer 2

Answer:

6 is the correct answer..