If k, 2k- 1 and 2k + 1 are three consecutive terms of an A.P., the value of k is - Mathematics

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If k, 2k- 1 and 2k + 1 are three consecutive terms of an A.P., the value of k is

(A) 2

(B) 3

(C) -3

(D) 5

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Solution

Correct answer: B
k, 2k - 1, 2k + 1 are in Arithmetic Progression
if a1, a2 and a3 are in A.P. then
a2 –a1 = a3 – a2
2a2 = a3 + a1
2 x (2k - 1) = (2k +1) + k
4k - 2 = 3k +1
k = 3

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2013-2014 (March) All India Set 2

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