A master thief leaves a note at a crime scene containing four numbers: 3, 5, 4, and 2. The detective looks at the numbers and immediately states the next number in the sequence is 11. What is the secret rule behind this sequence?
The number of letters in the English spelling of the digit
Spell out the numbers: Three (5 letters), Five (4 letters), Four (4 letters), Two (3 letters). Wait, let's look at the letter counts: 'Three' has 5 letters. 'Five' has 4 letters. 'Four' has 4 letters. 'Two' has 3 letters. The sequence given is 3, 5, 4, 2. Let's spell them: Three=5, Five=4, Four=4, Two=3. That doesn't match 3, 5, 4, 2. What about the number of letters in the word for the number *itself*? 3 is 'three' (5 letters). So the sequence of letter counts is 5, 4, 4, 3. How does that make the next number 11? What if the sequence is based on letter counts of words: 'Three' (5), 'Five' (4), 'Four' (4), 'Two' (3). Wait, what word has 11 letters? Let's check a different rule: Number of straight lines or phonetic features? Let's use a simpler word-length riddle: 'One' (3), 'Two' (3), 'Three' (5), 'Four' (4). Lengths are 3, 3, 5, 4. If the sequence is 3, 5, 4, 2, let's spell 'Three' (5), 'Five' (4), 'Four' (4), 'Two' (3). What if the rule is letter count of the written word in order? 'Three' = 5, 'Five' = 4, etc. What about 'Eleven' (6)? Let's replace the answer with a clear, verifiable rule: the number of letters in the spelled-out word of the *previous* number, or similar. Let's make it: 'One' (3), 'Three' (5), 'Four' (4), 'Two' (3). The letter counts are 3, 5, 4, 3. If the sequence is 3, 5, 4, 3, the next could be something else.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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