This is arithmetic progression based question from Chapter name- Arithmetic Progression
Chapter number- 9
Exercise – 9.4
In this question we have been given the arithmetic progression. Also we have to find if -150 is a term of the A.P. 11, 8, 5, 2, …
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Understanding CBSE Mathematics
Class :- 10th
Question no 3(iii)
Given, A.P. 11, 8, 5, 2, …
from given series,
a = 11 and d = a2 – a1 = 8 – 11 = -3
As we know that, to find nth term in an A.P = a + (n – 1)d
we have to find at which position -150 is present in given series,
a + (n – 1)d = -150
11 + (n – 1)(-3) = -150
11 – 3n + 3 = -150
3n = 150 + 14
3n = 164
n = 164/3, which is not a whole number.
Hence, -150 is not a term in the A.P.