Question

which term of ap 100,90,80....is 0

Answer 1

an=0
a=100
d=90-100=-10

therefore
an=a+(n-1)d
0=100+(n-1)*(-10)
0=100-10n+10
0=110-10n
10n=110
n=11

hence 11th term of the ap will be zero.

hope it helps you

Answer 2

The $11^{th}$ term of the AP is 0.

• The given AP is 100,90,80,.....
• The given AP has first term (a) = 100 and common difference (d) = Second term - First term = 90 - 100 = -10.
• Therefore the formula for $n^{th}$ of an AP is given as

$t_n = a + (n-1)d$

• We have to find the term which is zero.
• $t_n = 0$
• Now substituting the known values to find 'n' for which the term is zero.

0 = 100 + (n-1) (-10)

-100 = (n-1) (-10)

n - 1 =10

n = 11

• The $11^{th}$ term of the AP is zero.