Mirror and water image questions come in every ASO paper (2012: 4, 2015: 4, 2018: 6, 2021: 4, 2025: 3). The rule is simple, but options are designed to catch half-flipped answers, so check every part of the figure.
Mirror image (mirror on the left or right)
- Left and right swap; top and bottom stay the same.
- For words: the order of letters reverses and each letter is flipped. Letters that look the same in a mirror: A H I M O T U V W X Y, and digits 0 and 8.
Water image (water below), or a mirror above or below
- Top and bottom swap; left and right stay the same.
- For words: the order stays the same and each letter turns upside down. Letters that look the same: B C D E H I K O X, and digits 0 1 3 8.
Mirror time of a clock
Mirror time = 11:60 − actual time (8:40 → 3:20; 3:15 → 8:45). The same formula works backwards.
How to eliminate options
- Look at one distinctive part (a dot, an arrow head, a shaded corner) and see where it must go.
- Rule out options where that part is in the wrong place.
- For words, check the asymmetric letters (F, G, J, K, L, N, P, Q, R, S, Z and digits 2, 4, 7, 9). Wrong options leave one of them unflipped.
Characters that do not change
| In a mirror (left–right flip) | In water (top–bottom flip) | |
|---|---|---|
| Capital letters | A H I M O T U V W X Y (11 letters) | B C D E H I K O X |
| Small letters | i l o v w x | c l o x |
| Digits | 0 8 | 0 1 3 8 |
Words made only of these characters look the same in a mirror (TOMATO reversed reads OTAMOT) or in water (KICK, CODE, HIKE, CHIDE).
Small letters
- Mirror: b ↔ d and p ↔ q swap, because they are mirror shapes of each other.
- Water: b ↔ p and d ↔ q swap, and letters that go above or below the line (g, j, y, f, h, k) move to the other side of the line.
Where the mirror is placed
- Mirror on the left or right side: the image is exactly the same left–right flip.
- Mirror above or below the figure (such as MN drawn horizontally): it behaves like water and flips top to bottom.
- "Mirror image, then rotate 90° clockwise": do the flip first, then the turn. Don't do both at once.
Clock time formulas
- Mirror time = 11:60 − actual time. In general, image time = 11 h 59 min 60 s − actual time.
- Actual time and mirror time always add up to 12:00 (or 24:00 for times past 12).