Let the first three terms $2,\,p,\,q$ with $q\ne 2$ of a G.P. be respectively the $7^{\text{th}},\,8^{\text{th}}$ and $13^{\text{th}}$ terms of an A.P. If the $5^{\text{th}}$ term of the G.P. is the $n^{\text{th}}$ term of the A.P., then $n$ is equal to: