Question

which term of AP 27,24,21.... is zero options a) 8 ,b) 10 ,c) 9 ,d) 11​

Answer 1

Answer is (B) 10

method :

27 , 24 , 21

a = 27. d = 24-27 = -3. an = 0

an = a + (n-1) d

0 = 27 +( n- 1) -3

0 = 27 - 3n +3

0 = 30 - 3n

0 - 30 = - 3n

- 30 = - 3n

30 = 3n

3o = n

3

10 = n

n = 10

therefore n= 10