What Am I? The Grey Trail
Read the puzzle
Three clues describe one object. Clue 1: "I get shorter every time I work." Clue 2: "I leave a grey trail." Clue 3: "I have lead inside." The options are A: chalk, B: pencil, C: eraser, D: crayon. Which object fits all three clues?
Which object fits all three clues?
Think about the colour of the mark each one leaves.
Pencil
It gets shorter as it works, leaves a grey trail and has lead inside: B.
How to solve it
Check every option against all three clues.
Clue 1 fits all four: chalk, pencils, erasers and crayons all wear down as they are used, so it rules nothing out. Clue 2 does the work. Chalk leaves a white or coloured line, an eraser removes marks instead of leaving one, and a crayon leaves a coloured wax line. A pencil leaves a grey line. Clue 3 confirms it: a pencil has a core called lead (in fact graphite), and it gets shorter each time it is sharpened.
The trap is chalk, which also wears down and writes, but its trail is not grey and it has no lead.
Takeaway: when one clue fits everything, move on to the clue that splits the options.
Learn the method: Process of Elimination in Puzzles: Rule Out Until One Is Left
