Explanation:

- Start by identifying Prince's position: he is 5th from the right.

- Amit is 15th from the right, positioned between Prince and Aditya.

- Since Amit is exactly between Prince and Aditya, calculate Aditya’s position from the right:

- If Amit is 15th and Prince is 5th, Aditya must be equidistant from Amit on the opposite side, or 25th from the right.

- Aditya being 6th from the left suggests:

- Number of total people = Position of Aditya from left + Position from right - 1.

- 6 + 25 - 1 = 30.

Therefore, the correct option is Option:3, 30.