If the letters of an English alphabet are written in the reverse order, which letter will be the $5^{\text{th}}$ to the right of the $13^{\text{th}}$ letter from the left?

In the reversed alphabet series, the letters are arranged from Z to A:Position: 1st is Z, 2nd is Y, ..., 26th is A.We need to find the letter which is $5^{\text{th}}$ to the right of the $13^{\text{th}}$ letter from the left.
$$\text{Target Position from left}=13+5=18^{\text{th}}\text{ position from left}$$
In a reversed alphabet, the $18^{\text{th}}$ position from the left corresponds to the $18^{\text{th}}$ letter from Z.To find its position in the normal forward alphabetical order (A = 1, B = 2...):
$$\text{Forward Position}=27-18=9^{\text{th}}\text{ letter from A}$$
The 9th letter of the English alphabet is I.