Question

If the first term of an A.P. is $-1$ and common difference is $-3$, then its ${12}^{th}$ term is

• A. $34$
• B. $32$
• C. $-32$
• D. $-34$

Answer 1

The correct option is D $-34$

Given that,

The first term of an A.P. $\left(a\right)=-1$,

The common difference $\left(d\right)=-3$

To find out: ${12}^{th}$ term of the A.P.

We know that, $n^{th}$ term of any AP is given by:
$T_n=a+(n-1)d$
Hence,
$T_{12}=(-1)+(12-1)(-3)$

$\Rightarrow T_{12}=(-1)+\left(11\right)(-3)=-1-33$

$\therefore T_{12}=-34$

Hence, the ${12}^{th}$ term of the given A.P. is $-34$.