AP ICET 18 Sep 2021 Shift 1 Paper

Question Numbers : (61 to 65) In a certain code. the letters of the English alphabet $A, B, C, \dots, Z$ are given numbers $1,2,3$,$\dots, 26$ respectively. Then $n^{\text{th }}$ letter is coded as $r^{\text{th }}$ letter, where $1 \leq r \leq 26$ and $\frac{1}{n} \equiv r \pmod{26}$(that is 26 divides $\frac{1}{n-r}$ ). For example $9^{\text{th }}$ letter $I$ is coded as $21^{\text{st}}\ \text{letter}\ U$, since $99 \equiv 21$ (mod 26). For decoding reverse process is used. Based on this, answer questions 61 to 65 .