Question

Find the middle term of an A.P $-3,-1,1,...,33$

Answer 1

$a=-3,d=-1-(-3)=-1+3=2,l=33$

$n=\frac{l-a}{d}+1$

$=\frac{33+3}{2}+1=18+1=19$

$\therefore$ Total number of terms is $19$

$\left(\frac{19+1}{2}\right)={10}^{th}$ term is the middle term.

$t_{10}=a+9d=-3+9\times 2=-3+18=15$