The 6th and 17th terms of an A.P. are 19 and 41 respectively, find the 40th term.

Explanation

`T_ n`​`=a+(n−1)d`

Where a is the first term, d is the common difference and `T_n`​ denotes the n-th term of an AP.

Given:

`19=a+5d`

`41=a+16d`

Solving the above equations gives: `d=2,a=9`

Therefore, `T_40`​ `=9+39⋅2= 87`