CUET Preparation Today
The value of $3^{15}$ mod 7 is : |
5 1 2 6 |
6 |
The correct answer is Option (4) → 6 $3^1\,mod\,7=3$ $3^2\,mod\,7=2\,mod\,(7)$ $3^3\,mod\,7=-1\,mod\,(7)$ $3^4\,mod\,7=3×(-1)=-3≡4(mod\,7)$ $3^5\,mod\,7=3×4=12≡5(mod\,7)$ $3^6\,mod\,7=3×5=15≡1(mod\,7)$ $15=(3^6)^2×3^3$ $≡1^2×(-1)(mod\,7)$ $≡-1≡6(mod\,7)$ |
