Question

how many terms of the AP 18, 16, 14 be taken so that their sum is zero

Answer 1

sn=0
common difference=16-18=-2
now
$sn = \frac{n}{2} (2a + (n - 1)d)$
$0 = \frac{n}{2} (36 + (n - 1)( - 2))$
N=19