This is the Important question based on Arithmetic progression Chapter of R.S Aggarwal book for ICSE & CBSE

Board.

Here the AP and the last term of AP is given you have to find which term of the AP this must be.

This is the Question Number 10 Exercise 11 A of RS Aggarwal Solution.

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# Which term of the AP 72, 68, 64, 60, ….. is 0?

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AP is 72, 68, 64, 60, …..

Let

nth term is 0.Here,

First term = a = 72

Common difference = d = 68 – 72 = -4

a_n = a + (n – 1)d

0 = 72 + (n – 1)(-4)

-72 = -4(n – 1)

n – 1 = 18

n = 18 + 1 = 19

Therefore: 0 is the 19th term.