if `m t h` term of an A.P. is `n\ a n d\ n t h` term is `m ,` then write its `p t h` term.

Explanation

`a_m​=a+(m−1)d=n`

`a_n​=a+(n−1)d=m`


`(m−n)d=n−m
`

`=>d=−1`

`a+(1−m)=n`

`=>a=m+n−1`

...