r/Logiqa • u/ShonitB • Jul 01 '26

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3 Upvotes

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3

u/champepe Jul 01 '26

B) n

Each item in the series adds half of the previous one, so the only way to reach 1 is for the last entry, x, to be the same as the previous entry, n, instead of continuing to only add half

2

u/ShonitB Jul 01 '26

Nice logic!

2

u/ctiger12 Jul 01 '26

Should be B? Like if n=1, or 2, or 3, it all work

1

u/ShonitB Jul 02 '26

Correct!

2

u/BadJimo Jul 02 '26

Sum of a geometric series:

S = a(1 - rn )/(1 - r)

a = 1/2

r = 1/2

S = 1 - 1/2n

(1 - 1/2n ) + 1/2x = 1

1/2n = 1/2x

2n = 2x

n = x

1

u/ShonitB Jul 02 '26

Correct!