Question

What is the remainder when ${90}^{91}$ is divided by 13?

• A. 7
• B. 12
• C. 1

Answer 1

The correct option is B 12

Remainder obtained when $\frac{{90}^{91}}{13}=\frac{(-1{)}^{91}}{13}=\frac{-1}{13}$
Hence, remainder is - 1 or 12