‘Blood Type’ Logic Puzzle Solution <— Back to ‘Blood Type’ Logic Puzzle 1. Curie tells us Hawking and Crick are the only universal recipients, so they must be AB+ 2. Hawking tells us A+, A-, B+, and B- must be in the top row. Since Crick says only O and B types are in the last column, and Curie already has B+, Freud must be B- 3. Freud tells us everyone in Column 2 has positive Rh, so Carson must be A+. This leaves only A- for Gagarin. 1. Carson tells us Darwin can receive blood from only 1 other person, and not from anyone in the top row. Per Crick, Darwin has to be an O or B type. Freud (B-) can donate to any B type, so Darwin must be O+ or O-. Since Gagarin tells us there are 4 O+ types (not just one other person), Darwin must be O- 2. Darwin says no one in the bottom row can receive blood from both O- and B-. This eliminates all B and AB types, so all of the bottom row must be A or O types. Meitner must have positive Rh due to Freud’s clue. Since she cannot be O+ as she cannot be in a vertical pair (Gagarin’s clue), Meitner is left with A+ 3. Meitner says Elion can donate to exactly 2 other people in her row. Elion has to be an A or O type due to Darwin’s clue, therefore she must be an O type due to Crick’s clue. If she was O-, she could donate to everyone, so since she can only donate to 2 others, she must be O+ 4. Due to Gagarin’s vertical pair clue, Goodall must also be O+ 1. Due to Elion’s clue, Hodgkin must have a negative Rh. This means Elion, with an O+ blood type, cannot donate to her, so due to Meitner’s clue, Elion must be able to donate to Pavlov. This means Pavlov’s Rh factor is positive. The bottom row can only contain A or O blood types due to Darwin’s clue. Pavlov cannot be O+ since then due to Gagarin’s clue, there would be 2 O+ scientists in column 3 (impossible due to Goodall’s clue). Thus Pavlov must be A+ 2. Pavlov says Fermi shares a blood type with 2 others in his row. Therefore Fermi cannot be O+, as the only O+ left would then have to be in his column, not sharing his row. Einstein, Watson, Carver, and Jemison are eliminated from O+ contention due to the vertical pair rule (and Goodall’s rule). Hodgkin has a negative Rh due to Elion’s clue, which eliminates her and Bohr from O+ contention. This leaves Fossey and Newton as the remaining O+ pair. 1. Newton says no one in column 1 can donate to Fossey (O+), which means no one in Column 1 can be the other O- scientist who can donate to Darwin (Carson’s clue). Since there can only be one other O-, and Fermi shares a blood type with Carver and Watson (Pavlov’s clue), this leaves Jemison as the other O- scientist. 2. Per Jemison, every row contains both positive and negative Rh. Since Newton has positive Rh, the other 3 in his row, who share a blood type, must be negative. Watson must be B- or O- due to Crick’s rule. Since there are no O- slots left, Watson must be B-, which means Carver and Fermi are also B- 1. Hodgkin must be A- or O- due to Meitner’s and Darwin’s clues. Since the O- slots are now taken, she must be A- 2. Hodgkin says only one scientist can donate to exactly 2 other people. A+, A-, B-, O+, and O- can all donate to more than 2 already. AB+ can each donate to only 1 other person. This leaves B+ and AB- with 2 current recipients on the board (the 2 AB+). Since Fossey tells us Curie (B+) can donate to another person in her column, this leaves AB- as the only possible answer. So there must be exactly 1 AB- scientist. We know Bohr has a positive Rh due to Elion’s clue. So Einstein must have the AB- blood type. 3. Since Fossey tells use Curie (B+) can donate to 1 other person in her column, and both AB+ spots are taken per Curie’s clue, Bohr must be B+ 4. Congratulations!