Riddles, one at a time
One Stroke: Twin X
Without lifting your pen and without going over any line twice, which figure can you draw?
Count the lines at each dot, including where the X lines cross.
D
Only D has 2 odd dots. The others have 4 or more.
Three Rings
How many closed areas are there inside the rings? Do not count the space around them.
Count the areas inside one ring, two rings and all three.
7
3 parts inside one ring, 3 where two rings overlap, and 1 middle where all 3 meet: 3 + 3 + 1 = 7.
Two Candles: Twice as Tall
Two candles of the same height are lit together and burn at a steady rate. A lasts 4 hours, B lasts 6 hours. After how many hours is B twice as tall as A?
A loses a quarter of its height each hour, B loses a sixth.
3 hours
After 3 h, A has 1/4 left and B has 1/2 left: twice.
Three Level Scales
How many circles balance the last scale?
5 CIRCLES
Square = 2 circles, triangle = 3 circles.
Turn the Crank
The big gear turns clockwise. Which lantern goes UP?
LANTERN C
Each mesh and the crossed belt flip the spin.
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.