Riddles, one at a time
Gem Finder: Three Gems, One Blank
A number counts the gems in the 8 tiles around it; numbered tiles have none. Which lettered tile has NO gem?
Check every number around the lettered tiles.
D
D touches a 0, so it is empty; the numbers force gems under A, B and C.
Split 8 Litres
Fewest pours to share it 4 L and 4 L?
Only the 8 L and 5 L jugs can end with 4 L. Use the 3 L jug as a measure.
7 pours
8→5, 5→3, 3→8, 5→3, 8→5, 5→3, 3→8: 4 L and 4 L.
Three Turning Rings
At which step number are all three gems at the top again?
36 STEPS
Notches 9, 6 and 4: the first common multiple is 36.
Crack the Lock
Which 3-digit code opens the lock?
738
3 sits in the middle, 8 stays last, 7 goes first.
One Word, Three Pairs
WORK
Firework, workshop, homework, workout, network, workbook.
Two Candles: 20 cm and 15 cm
After how many hours are they the same height?
How big is the gap at the start, and how fast does it close?
2 hours
After 2 h: A is 20 − 8 = 12 cm, B is 15 − 3 = 12 cm.