alleryStart learning →As per your syllabus, the AP 21, 18, 15,... has common difference −3. Which term is −81?
AThe 28th term
BThe 30th term
CThe 35th term (since 21 + (n−1)(−3) = −81 → n−1 = 34 → n = 35)
D−81 is not a term
Answer & Solution
Correct answer: C. The 35th term (since 21 + (n−1)(−3) = −81 → n−1 = 34 → n = 35)
As per your syllabus, a = 21, d = −3, set 21 + (n−1)(−3) = −81
We have → (n−1)(−3) = −102 → n − 1.
That is → (n−1)(−3) = 34 → n.
So → (n−1)(−3) = 35.
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