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Question
The 7th term of an AP is –1 and its 16th term is 17. The nth term of the AP is ______.
Options
(3n + 8)
(4n – 7)
(15 – 2n)
(2n – 15)
MCQ
Fill in the Blanks
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Solution
The 7th term of an AP is –1 and its 16th term is 17. The nth term of the AP is (2n – 15).
Explanation:
T7 = –1 ⇒ a + 6d = –1. ...(i)
T16 = 17 ⇒ a + 15d = 17. ...(ii)
On solving (i) and (ii), we get a = –13 and d = 2.
∴ Tn = a + (n – 1)d
= –13 + (n – 1) × 2
= (2n – 15)
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