Question

If three times the $9$th term of an A.P is equal to five times its $13$th term, then which of the following term will be zero.

• A. $26$th
• B. $19$th
• C. $21$st
• D. $36$th

Answer 1

The correct option is B $19$th

According to the question $3(a+8d)=5(a+12d)$
$\Rightarrow 3a+24d=5a+60d$
$\Rightarrow 2a+36d=0$
$\Rightarrow a+18d=0$
$\Rightarrow a+(19-1)d=0$
Hence ${19}^{th}$ term is zero