Solution:
AP is 21, 18, 15, …n
Here,
a = 21,
d = 18 – 21 = -3,
l = 0
Tn (l) = a + (n – 1) d
⇒ 0 = 21 + (n – 1) x (-3)
⇒ 0 = 21 – 3n + 3
⇒ 24 – 3n = 0
⇒ 3n = 24
⇒ n = 8 .
0 is the 8th term.
Solution:
AP is 21, 18, 15, …n
Here,
a = 21,
d = 18 – 21 = -3,
l = 0
Tn (l) = a + (n – 1) d
⇒ 0 = 21 + (n – 1) x (-3)
⇒ 0 = 21 – 3n + 3
⇒ 24 – 3n = 0
⇒ 3n = 24
⇒ n = 8 .
0 is the 8th term.