Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Numbers, Quantification and Numerical Applications

Question:

The least non-negative remainder when $3^{51}$ is divided by 7 is:

Options:

2

3

6

5

Correct Answer:

6

Explanation:

The correct answer is Option (3) → 6

$3^6=729.$

$729 \equiv 1 \pmod{7}.$

$3^{51}=(3^6)^8\cdot3^3.$

$3^{51}\equiv1^8\cdot27\pmod{7}.$

$27\equiv6\pmod{7}.$

$6.$