The Clock in the Water
Read the puzzle
A clock's real face is hidden; only its reflection in still water below is visible. The water swaps top and bottom but not left and right. In the reflection, 6 is at the top, 12 at the bottom, 3 on the right and 9 on the left. The short hour hand points up-left, 55 degrees left of straight up. The long minute hand points down-left, 60 degrees left of straight down. What time does the real clock show?
Top and bottom swap in the water. What time does the real clock show?
7:50
Water flips top and bottom: flip the hands back up.
How to solve it
Undo the flip. Water reflects top to bottom, so every point keeps its left-right position but swaps its height. That is why the reflected face shows 6 at the top and 12 at the bottom, while 3 and 9 stay put.
Read the hands against the reflected numbers, not against a normal clock. Going down from the 9 toward the 12 at the bottom, the marks are 10 and then 11. The minute hand points at the first of these, the 10, which is the 50-minute mark. Going up from the 9 toward the 6 at the top, the marks are 8 and then 7. The hour hand sits just past the 8 mark, a little toward the 7, so the hour is 7, nearly 8.
So the real clock shows 7:50, ten to eight. The hour hand being almost at 8 fits: at 50 minutes past, it should be most of the way from 7 to 8.
The usual wrong answer is 10:40, which comes from reading the reflection as if it were an ordinary clock face. Quick check: flip the hands back up in your head and the minute hand points to the 10.
Learn the method: How to Solve Mirror Image Puzzles: Clocks, Letters, Tiles and Light
