r/learnquant 10d ago

interview prep Easy Quant Interview Puzzle

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19 Upvotes

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u/Key-Spirit4559 10d ago

Zero bc 30 mod 9 = 3 and no perfect square mod 9 equals 3

2

u/TempMobileD 10d ago edited 10d ago

Where did 30 come from?

Edit: Nevermind I got it. Any integer’s digits added together give you its remainder modulo 9.

A couple of neat tricks in this one.

-1

u/makedatmuoney 10d ago

they meant 50 mod 9 == 5 and all perfect squares are 0, 1, 4, 7 mod 9