Q8 of 49 Page 1

Find whether -150 is a term of the A.P. 17, 12, 12, 7, 2, ….?

To solve this question, we equate nth term of this A.P. as -150. If n is a natural number then it lies in the A.P. otherwise it doesn’t.

For the A.P. series given,


a=17,


d=12-17=-5


nth term of A.P. = a + (n-1)d


= 17 + (n-1)(-5)=-150


⇒ (n-1)(-5)=-150-17=-167


⇒ n-1=167/5


⇒ n= 172/5


Here we see that n is not a natural number,
∴ -150 is not a term of this A.P.


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