Riddles, one at a time
Two Jugs: 5 L and 7 L
Filling, emptying or pouring a jug counts as 1 move each. Fewest moves to get exactly 6 L in the 7 L jug?
Always fill the 7 L jug and pour it into the 5 L jug.
10 moves
Fill 7, pour into 5, empty 5, pour 2 L over, fill 7, top up 5, empty 5, pour 4 L over, fill 7, top up 5.
Shaded Part: The Pinwheel
What fraction of the square is gold?
Find the dark area instead: one middle square plus four thin slivers.
2/3
The dark part is 1 middle square + 4 halves = 3 of 9 squares, so gold is 6/9 = 2/3.
What Am I? Roads Without Cars
Which object fits all three clues?
A globe shows roads and rivers too. Can it fold into a pocket?
Map
Its roads have no cars, its rivers have no water, and it folds into a pocket: A.
Lighthouse Flashes
A lighthouse flashes evenly. From the 1st flash to the 6th takes 5 seconds. How long from the 1st flash to the 11th?
Count the gaps between flashes, not the flashes.
10 seconds
Flash 1 to flash 6 is 5 gaps, so each gap is 1 second. Flash 1 to 11 is 10 gaps.
Hands Apart: 9:45
What is the SMALLER angle between the hands?
The hour hand moves 30° each hour. How far has it gone after 45 minutes?
22.5°
The minute hand is on 9; the hour hand is 3/4 of the way to 10: 3/4 × 30° = 22.5°.