If a_1, a_2, ......... are in A.P , 1/(√(a_1) + √(a_2)) + 1/(√(a_2) + √(a_3)) + ......... + 1√(a_n) + a_n+1 then , is equal to

(B) (n - 1)/(√(a_1) + √(a_n))

CAT 2019 Slot 1 QA Q20 Progressions & Series

Question 20 of the Quantitative Ability (QA) section, CAT 2019 Slot 1, with CAT's official answer.

If a₁, a₂, ......... are in A.P , \(\frac{1}{\sqrt{a_1} + \sqrt{a_2}}\) + \(\frac{1}{\sqrt{a_2} + \sqrt{a_3}}\) + ......... + \(\frac{1}{\sqrt{a_n} + \sqrt{a_{n+1}}}\) then , is equal to

A
\(\frac{n}{\sqrt{a_1} + \sqrt{a_{n+1}}}\)
B
\(\frac{n - 1}{\sqrt{a_1} + \sqrt{a_n}}\)
C
\(\frac{n}{\sqrt{a_1} - \sqrt{a_{n+1}}}\)
D
\(\frac{n - 1}{\sqrt{a_1} + \sqrt{a_{n-1}}}\)

Answer: (A) n√(a_1) + a_n+1 Progressions & Series MCQ

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CAT 2019 Slot 1 QA Q20 Progressions & Series

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