Riddles, one at a time
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.
One Is Mirrored
Which tile is a mirror image?
E
Turn every tile upright: only E faces the wrong way.
Climbing Robot
A robot climbs a 10 m wall. Each day it climbs 3 m; each night it slips back 2 m. On which day does it reach the top?
On the last day it does not slip back.
Day 8
After night 7 it is at 7 m; day 8 takes it to 10 m.
Fewest Tokens: Pay 6
Which tokens pay 6 with the fewest tokens?
Biggest first is not always fewest. Try every pair.
3 + 3
Just 2 tokens. Biggest first, 4 + 1 + 1, needs 3.
Follow the Light
Colours mix like paint. Which door does the beam light, and in what colour?
D, ORANGE
Mirrors turn it; red and yellow panes make orange.
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.