Question

Which term of the AP 21 , 18 , 15 , _____ is 0


please solve​

Answer 1

AP must be

21,18,15,12,9,6,3,0

so 8th term must be 0

Answer 2

Answer:

The first term of the AP, a = 21

The common difference, d = 18 – 21 = -3

now (nth term) = a + (n−1) d

⇒ 0 = a + (n−1) d

⇒ 0 = 21 + (n−1) (−3)

⇒ n − 1 = -24 / -3

⇒ n − 1 = 7

⇒ n = 7+1

∴ n = 8

Hence,the required term is 8.