The 12th term of an AP is -41 given that the first term is 3 find the 20th term

Answer 1

In AP n- th term:

an = a + ( n - 1 ) d

where

a = first term

d = common difference

In this case:

a = 3

a12 = a + 11 d = - 41

3 + 11 d = - 41

Subtract 3 to both sides.

11 d = - 44

d = - 44 / 11

d = - 4

a20 = a + 19 d = 3 + 19 • ( - 4 ) =

3 - 76 = - 73