An Important question based on Arithmetic progression Chapter of R.S Aggarwal book for ICSE & CBSE Board.

Here An AP, Common difference between its terms and the first and its nth term is given. you have to find the n in the given Question

This is the Question Number 29 Exercise 11 A of RS Aggarwal Solution.

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# In a flower bed, there are 43 rose plants in the first row, 41 in the second 39 in the third, and so on. There are 11 rose plants in the last row. How many rows are there in the flower bed?

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In AP form : 43,41,39,37,35……11

(d=-2)

an=a+(n-1)d

11 = 43 +(n-1)-2

11-43 = (n-1)-2

-32/-2 = n-1

16 + 1=n

n=17 therefore there are 17 rows in flower bed