COMEDK · Maths · 17. Mathematical Reasoning
In the group \(\{1,2,3,4,5,6\}\) under multiplication \(\bmod 7,2^{-1} X_{7}^{4}=\)
- A 1
- B 4
- C 2
- D 3
Answer & Solution
Correct Answer
(C) 2
Step-by-step Solution
Detailed explanation
Under Multiplication Modulo 7 , inverse of 2 is \(2 \times 4=1(\bmod 7)\) Hence, \(\quad 2^{-1}=4\) Now, \(2^{-1} \times 4=4 \times 4=16\) Now, \(\quad 16=2 \times 7+2\) Hence dividing 16 by 7 gives a remainder 2 , Therefore, value of above multiplication mod is 2.
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