| Clue | Length | Answer |
|---|---|---|
| Difficult problem | 4 letters | crux |
| Difficult problem | 5 letters | poser |
| Difficult problem | 6 letters | puzzle |
| Difficult problem | 6 letters | enigma |
| Difficult problem | 7 letters | puzzler |
| Difficult problem | 7 letters | toughie |
| Difficult problem | 7 letters | dilemma |
| Difficult problem | 7 letters | stumper |
| Difficult problem | 8 letters | ratsnest |
| Difficult problem | 8 letters | stickler |
| Difficult problem | 9 letters | conundrum |
| Difficult problem | 11 letters | brainteaser |
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