Question

Calculate the ${15}^{\text{th}}$ term of the A.P. $-3,-4,-5,-6,-\mathrm{7....}$

• A. $-13$
• B. $-15$
• C. $-17$
• D. $-19$

Answer 1

Answer: (C)

$-17$

Let the general form of A.P., $a_n=a+(n-1)d$
Common difference, $d=-1$
$a_{15}=?$
$a_n=a+(n-1)d$
$a_{15}=-3+(15-1)\times -1$
$a_{15}=-3-14$
$a_{15}=-17$