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AP EAMCET · Maths · Binomial Theorem

If \(k\) is a positive integer and \(10^k\) is a divisor of the number \(9^{11}+11^9\), then the greatest value of \(k\) is

  1. A 1
  2. B 2
  3. C 3
  4. D 4
Verified Solution

Answer & Solution

Correct Answer

(B) 2

Step-by-step Solution

Detailed explanation

\(9^{11} \pmod{100}\): \(9^1=9, 9^2=81, 9^5 \equiv 49 \pmod{100}\) \(9^{10} \equiv (9^5)^2 \equiv 49^2 = 2401 \equiv 1 \pmod{100}\) \(9^{11} \equiv 9^{10} \cdot 9 \equiv 1 \cdot 9 \equiv 9 \pmod{100}\) \(11^9 \pmod{100}\):…