JEE Main 2020 — Sequences And Series Question with Solution
From: JEE Main 2020 (Online) 2nd September Evening Slot
Question
If the sum of first 11 terms of an A.P.,
a1, a2, a3, .... is 0 (a 0), then the sum of the A.P.,
a1 , a3 , a5 ,....., a23 is ka1 , where k is equal to :
a1, a2, a3, .... is 0 (a 0), then the sum of the A.P.,
a1 , a3 , a5 ,....., a23 is ka1 , where k is equal to :
Choose an option
Show full solutionCorrect option: D
Correct answer
D-
Step-by-step explanation
Let common difference be d.
a1 + a2 + a3 + ... + a11 = 0
= 0
a1 + 5d = 0
d = .....(1)
Now a1 + a3 + a5 + ... + a23
= (a1 + a23)
= (a1 + a1 + 22d) × 6
= 6
=
k =
a1 + a2 + a3 + ... + a11 = 0
= 0
a1 + 5d = 0
d = .....(1)
Now a1 + a3 + a5 + ... + a23
= (a1 + a23)
= (a1 + a1 + 22d) × 6
= 6
=
k =
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This is a previous-year question from JEE Main 2020, covering the Sequences And Series chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.