1 7 1 6 + 1 8 1 7 + 1 9 1 8 + ⋯ + 3 3 3 2 □ 1 6
What sign < , = , or > should be in the box?
This is part of the series: It's easy, believe me!
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Great solution. Still wonder why a lot of people get tricked.
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I don't know.
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I think it's because they think there are only 16 terms on the LHS.
Maybe they solve this problem this way: 1 7 1 6 < 1 1 8 1 7 < 1 1 9 1 8 < 1 . . . 3 3 3 2 < 1 So that: 1 7 1 6 + 1 8 1 7 + 1 9 1 8 + . . . + 3 3 3 2 < 1 6 I made this question just to see if people can get tricked. And it seems like some people do get tricked.
There are seventeen terms here. The first one is equal to 1 6 / 1 7 ; the other ones are all greater.
(Consider, e.g. that 1 8 1 7 = 1 − 1 8 1 > 1 − 1 7 1 = 1 7 1 6 .)
Thus we have 1 7 1 6 + 1 8 1 7 + ⋯ + 3 3 3 2 > 1 7 × 1 7 1 6 + 1 7 1 6 + ⋯ = 1 7 ⋅ 1 7 1 6 = 1 6 .
I liked this answer. Its so simple and clever!
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S = 1 7 1 6 + 1 8 1 7 + 1 9 1 8 + ⋯ + 3 3 3 2 = 1 7 1 7 − 1 + 1 8 1 8 − 1 + 1 9 1 9 − 1 + ⋯ + 3 3 3 3 − 1 = 1 7 − ( 1 7 1 + 1 8 1 + 1 9 1 + ⋯ + 3 3 1 ) > 1 7 − ( 1 7 1 + 1 7 1 + 1 7 1 + ⋯ + 1 7 1 ) > 1 7 − 1 = 1 6
⟹ S > 1 6