In a 3x3 Latin square using A, B, C: row 1 is [A, B, C], row 2 has B in column 2. What is cell(2,1)?
💡 Explanation
Wait, if cell(2,2) = B, then row 2 must contain A and C in some order. Thus cell(2,1) can be A or C. But let's check column constraints: col 2 already has B in row 1, so row 2 col 2 CANNOT be B. Let's fix this logic: row 2 cannot have B in column 2. Thus, the question premise is invalid or it must be cell(2,2) = C. Let's rephrase: row 2 has C in column 2, and row 1 is [A, B, C]. What is cell(2,1)? Since col 1 has A in row 1, and row 2 has C in col 2, cell(2,1) must be C or A? No, col 1 has A, so row 2 col 1 must be B or C. Since row 2 already has C in col 2, cell(2,1) must be B.