Question

Find the ${12}^{th}$ term from the end of the A.P.

$2,4,6,...,100.$

Answer 1

We have to find out the ${12}^{th}$ term of an A.P. from the end.

So, we have to assume that the last term is the first term and the last term in this A.P. is $100.$

let the first term be $100$ and $d=-2$

$a_{12}=a+(n-1)d$

$=100+(12-1)(-2)$

$=(100-11\times 2)$

$=100-22$

$=78$

So, the ${12}^{th}$ term of the A.P. from the end will be $78$