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The remainder when \(7^{103} + 7^{101}\) is divided by \(9\) is __________

Question and options

The remainder when 7103+71017^{103} + 7^{101} is divided by 99 is __________
  1. 8
  2. 4
  3. 2
  4. 7

Answer and explanation

Correct answer: C - 2

The remainder is 22. Since 73≡1(mod9)7^3\equiv1\pmod9, the exponents 103103 and 101101 reduce to 11 and 22 in the cycle, giving residues 77 and 44. Their sum 1111 leaves remainder 22, whereas treating 101101 as a multiple of three incorrectly gives 7+1=87+1=8.

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  • IPMAT Indore

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