Hey!
I'm Norbert from Germany and I found the following problem which was on Harvards Admissions Test in 1869:
a+b+c=214
a+b=3c
c+b=0.5a
I solved the problem pretty quick and was wondering if there were more solutions other than real ones.
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It's a linear system with one unique solution made of rational numbers (428/3, 107/6, 107/2). I don't see how a complex solution is possible.