Question

nth term of an AP is 0. If AP is 63, 60, 57…, then find the value of n.

A 18 Correct Answer Incorrect Answer
B 20 Correct Answer Incorrect Answer
C 22 Correct Answer Incorrect Answer
D 24 Correct Answer Incorrect Answer

Solution

Tn = a + (n – 1)d Where, a = first term and d = common difference Here, a = 63 d = 60 – 63 = - 3 T = a + (n – 1) d ⇒ 0 = 63 + (n – 1) × (- 3) ⇒ (n – 1) × (-3) = - 63 ⇒ n – 1 = 63/3 ⇒ n – 1 = 21 ⇒ n = 22 ∴ There are 22 terms of the A P

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