Question

Question 4
The ${11}^{th}$ term of the AP $-5,\frac{-5}{2},0,\frac{5}{2},\cdots \cdots$ is

A) -20
B) 20
C) -30
D) 30

Answer 1

$GivenAP:-5,-\frac{5}{2},0,\frac{5}{2},...$
$Here,a=-5,d=a_2-a_1=\frac{-5}{2}+5=\frac{5}{2}$
$\therefore a_{11}=a+(11-1)d[\because a_n=a+(n-1\left)d\right]$
$=-5+\left(10\right)\times \frac{5}{2}$
$=-2+25=20$