Question

Which term of the A.P., $84,80,76,..$ is $0?$

• A. ${18}^{th}$ term
• B. ${20}^{th}$ term
• C. ${22}^{nd}$ term
  
• D. ${24}^{th}$ term

Answer 1

The correct option is C ${22}^{nd}$ term

The given sequence is an AP in which first term $a=84$ and common difference $d=-4$.

We have to find value of n for which $a_n$ is $0$.

Then,
$a+(n-1)d=0$
$\Rightarrow 84+(n-1)\times -4=0$
$\Rightarrow 88-4n=0$

$\Rightarrow n=22$
Hence, ${22}^{nd}$ term is $0$.