Mirror & Water Images

Subject: Mental Ability | Frequency: 1-2 questions per APPSC paper | Time: 30-45 sec/question

Introduction

Mirror image questions test lateral inversion (left-right swap); water image questions test vertical inversion (top-bottom swap). APPSC commonly asks mirror images of figures/letters and clock mirror problems. The clock formula and symmetric letter list are the two highest-yield things to memorize.

Core Method

For Mirror Images (Lateral Inversion):

1. Identify mirror position — right, left, top, or bottom?
2. Vertical mirror (right/left): left-right swap; top-bottom unchanged
3. Horizontal mirror (top/bottom): top-bottom swap; left-right unchanged
4. Check endpoints first — first element becomes last, last becomes first
5. Eliminate using 1-2 distinctive features

For Water Images (Vertical Inversion):

1. Flip vertically — top becomes bottom, bottom becomes top
2. Left-right stays the same — no lateral inversion
3. Each element inverts individually

Key Rules

Symmetric Letters (same in vertical mirror)

Capital: A, H, I, M, O, T, U, V, W, X, Y

Clock Mirror Formula

Worked Examples — Easy

Q1: Mirror image of "AMBULANCE" (vertical mirror on right):

• Reverse letter order: ECNALUBMA
• Each letter is also laterally inverted
• This is why ambulances print the word reversed!
• Answer: ECNALUBMA (each letter flipped)

Q2: What time does a clock show in a mirror if actual time is 3:15?

• Formula: 11:60 - 3:15 = 8:45

Q3: Mirror image of number "318" (mirror on right):

• Reverse order: 813
• Each digit also laterally inverts (8 stays symmetric, 1 stays, 3 flips)
• Answer: 813 with individual digit flipping

Worked Examples — Medium

Q4: What time shows in mirror if actual time is 7:25?

• 11:60 - 7:25 = 4:35

Q5: What time shows in mirror if actual time is 11:40?

• Since 11:01-12:59 range: 23:60 - 11:40 = 12:20

Q6: Water image of the letter "F":

• F flipped upside down: horizontal bars still go right, but top bar is now at bottom
• The vertical stroke stays; top horizontal bar moves to bottom position
• Answer: Looks like an upside-down F (vertical bar with horizontal bars at bottom)

Worked Examples — Hard

Q7: Mirror image of "5:50" on a digital clock:

• Time reversal: 11:60 - 5:50 = 6:10
• On digital display, each digit must also be mirror-checked
• Answer: 6:10 (with digitally appropriate rendering)

Q8: What is the water image of "QUALITY"?

• Each letter flips upside down
• Letters that stay same in water reflection: I, O, T, X (symmetric about horizontal axis)
• Q, U, A, L, Y all change form when flipped vertically
• Technique: Check if the answer options preserve I and T while changing others

Q9: A triangle pointing up-right with a dot in the top-right corner. Mirror image (mirror on right)?

• Triangle now points up-left (left-right swap)
• Dot was in top-right → now in top-left
• All left-right positions swap; up-down unchanged
• Answer: Triangle pointing up-left, dot in top-left

Shortcuts & Tricks

Common Mistakes

1. Confusing mirror and water images — mirror = left-right swap; water = up-down swap
2. Wrong mirror position — always check where the mirror is placed relative to the object
3. Forgetting individual element inversion — each letter/number also gets inverted, not just reordered
4. Clock time range error — using 11:60 for times above 11:00 (should use 23:60)
5. Assuming all letters change — symmetric letters (A,H,I,M,O,T,U,V,W,X,Y) stay the same

Exam Strategy

• Master the clock formula (11:60 / 23:60) — these are the most frequently tested
• Memorize the symmetric letter list — instant elimination tool
• For figure-based questions, focus on ONE distinctive feature to eliminate wrong options
• APPSC keeps difficulty at easy-to-medium
• Time: 30-45 seconds per question

Practice Questions

1. Clock shows 2:30 in mirror. Actual time? → 11:60 - 2:30 = 9:30
2. Mirror image of "STOP" → reversed: POTS (with each letter laterally inverted)
3. Water image of "M" → W (flipped upside down)
4. Which letter looks the same in a mirror? A, B, C, D → A (symmetric)
5. Clock shows 12:15 in mirror. Actual time? → 23:60 - 12:15 = 11:45

Key Terms / Formulas