Mirror Water Image
Key Concepts & Formulas
| # | Concept | Quick Explanation |
|---|---|---|
| 1 | Mirror Image Rule | Letters with horizontal symmetry (B, C, D, E, H, I, K, O, X) appear same in mirror |
| 2 | Water Image Rule | Letters with vertical symmetry (A, H, I, M, O, T, U, V, W, X, Y) appear same in water |
| 3 | Clockwise Rotation | Mirror image = 180° clockwise rotation of original |
| 4 | Inversion Principle | Water image = vertical inversion (top becomes bottom) |
| 5 | Number Symmetry | 0, 1, 8 remain same in both mirror and water images |
| 6 | Direction Change | Left ←→ Right in mirror, Up ←→ Down in water |
| 7 | Combined Images | For mirror+water: first apply mirror, then water transformation |
10 Practice MCQs
Q1. What is the mirror image of "RAILWAY"? A) YAWLIAR B) YA⅃IΛЯ C) ЯAI⅃WAY D) YAWLIAЯ
Answer: B) YA⅃IΛЯ
Solution:
- R → Я (backward R)
- A → Λ (inverted V shape)
- I → I (symmetrical)
- L → ⅃ (backward L)
- W → W (symmetrical)
- A → Λ (inverted V shape)
- Y → Y (symmetrical)
Shortcut: Write on paper, hold to mirror - read reflected image
Concept: Mirror Image - Letter transformation rules
Q2. Find the water image of "STATION"? A) NOITA⊥S B) NOITATS C) S⊥ATION D) NOITΛ⊥S
Answer: A) NOITA⊥S
Solution:
- Write vertically and flip upside down
- S → S (remains same)
- T → ⊥ (inverted T)
- A → Λ (inverted A)
- T → ⊥ (inverted T)
- I → I (remains same)
- O → O (remains same)
- N → N (remains same)
Shortcut: Turn paper upside down, read from bottom to top
Concept: Water Image - Vertical inversion principle
Q3. Which number looks same in mirror image? A) 2 B) 3 C) 0 D) 5
Answer: C) 0
Solution:
- 2 → backward 2 (different)
- 3 → backward 3 (different)
- 0 → 0 (symmetrical, same)
- 5 → backward 5 (different)
Shortcut: Numbers 0, 1, 8 have mirror symmetry
Concept: Mirror Image - Number symmetry rules
Q4. A train board shows "EXPRESS 123". What appears in the water reflection of a puddle? A) 321 SSƎɹԳPXƎ B) 321 SƧƎɹԳPXƎ C) ƎXPԳƎɹƧƧ 321 D) 321 SSƎɹԳPXƎ
Answer: A) 321 SSƎɹԳPXƎ
Solution:
- Reverse entire string: “321 SSƎɹԳPXƎ”
- E → Ǝ
- R → ɹ
- P → Գ
- Numbers 1,2,3 flip vertically but remain recognizable
Shortcut: Reverse string order + flip each character vertically
Concept: Combined water image with alphanumeric
Q5. If a station clock shows 3:00, what time appears in its mirror? A) 9:00 B) 12:00 C) 9:30 D) 3:00
Answer: A) 9:00
Solution:
- Mirror time = 12:00 - actual time
- 12:00 - 3:00 = 9:00
- Check: 3 and 9 are opposite on clock face
Shortcut: Mirror time = (12:00 - given time) OR (24:00 - given time)
Concept: Mirror Image - Clock dial symmetry
Q6. A ticket shows seat number "B3". What appears in the mirror at the ticket counter? A) ƎƸ B) ƸƎ C) 3B D) ɘƨ
Answer: B) ƸƎ
Solution:
- Reverse order: 3B
- B → ɘ (backward B)
- 3 → ƨ (backward 3)
- Result: ƨɘ but written as ƸƎ in options
Shortcut: Reverse string + flip each character horizontally
Concept: Mirror Image - Alphanumeric combinations
Q7. The word "RAILWAY" is written on a train. A person in a helicopter sees its water reflection in a river. What appears? A) YAWLIAR B) YΛW⅃IΛЯ C) ЯAI⅃WAY D) YΛWIΛЯ
Answer: B) YΛW⅃IΛЯ
Solution:
- First apply mirror: ЯAI⅃WAY
- Then apply water: YΛW⅃IΛЯ (reverse order + vertical flip)
- Y → Y (same upside down)
- A → Λ (inverted)
- W → W (same)
Shortcut: Mirror first, then water transformation
Concept: Combined mirror + water image
Q8. A platform display shows "TRAIN ★ 180". In the mirror reflection, what symbol sequence appears? A) 081 ★ NIART B) 081 ★ ЯAIИT C) 081 ★ TИIΛЯ D) 081 ★ ЯИIΛЯ
Answer: C) 081 ★ TИIΛЯ
Solution:
- Reverse entire string: “081 ★ TИIΛЯ”
- T → T (symmetrical)
- R → Я
- A → Λ
- I → I
- N → И
- ★ → ★ (symmetrical)
- Numbers 1,8,0 flip appropriately
Shortcut: Star symbol remains same, focus on letter transformations
Concept: Complex string with special characters
Q9. If "DELHI" is written on transparent paper and viewed through water droplets on glass, what appears? A) IHᄅƎD B) IH⅃ƎD C) IHIƎD D) IHᄅED
Answer: B) IH⅃ƎD
Solution:
- Water image = vertical inversion
- Reverse order: IHLED
- D → D (symmetrical vertical)
- E → Ǝ (inverted)
- L → ⅃ (inverted)
- H → H (symmetrical)
- I → I (symmetrical)
Shortcut: Transparent paper + water = water image only
Concept: Water Image - Transparent medium scenario
Q10. A railway sign shows "CAUTION ⚠ 50m". In the driver's mirror, what complete sequence appears? A) m05 ⚠ NOITAUC B) m05 ⚠ ИOITΛƆU C) m05 ⚠ ИOITΛUC D) m05 ⚠ ИOITΛ∩Ɔ
Answer: B) m05 ⚠ ИOITAƆU
Solution:
- Reverse string: “m05 ⚠ ИOITΛƆU”
- C → Ɔ (backward C)
- A → Λ (inverted)
- U → ∩ (inverted U)
- T → T (symmetrical)
- I → I
- O → O
- N → И (backward N)
- ⚠ → ⚠ (symmetrical)
- m → m (symmetrical)
Shortcut: Warning symbols usually symmetrical, focus on text
Concept: Mirror Image - Real-world signage application
5 Previous Year Questions
PYQ 1. Find the water image of "RAILWAY" [RRB NTPC 2021 CBT-1]
Answer: YΛW⅃IΛЯ
Solution: Reverse the word and flip each letter vertically: R→Я, A→Λ, I→I, L→⅃, W→W, A→Λ, Y→Y
Exam Tip: Write the word upside down on paper, then read from bottom
PYQ 2. What is the mirror image of "STATION 15"? [RRB Group D 2022]
Answer: S1 NOITA⊥S
Solution: Reverse entire string: “S1 NOITA⊥S” where T→⊥, S→S, 1→1 (backward), 5→Ƨ
Exam Tip: Numbers 2,3,4,5,7 change in mirror; 0,1,8 remain same
PYQ 3. If a clock shows 2:45, what time appears in mirror? [RRB ALP 2018]
Answer: 9:15
Solution: Mirror time = 11:60 - 2:45 = 9:15 (or 12:00 - 2:45 = 9:15, adjust for 12-hr format)
Exam Tip: For mirror clock: Subtract from 12:00 or 24:00
PYQ 4. Find the water image of "ENGINE" [RRB JE 2019]
Answer: ƎИIGИƎ
Solution: E→Ǝ (inverted), N→И (backward), G→G (symmetrical), I→I, N→И, E→Ǝ
Exam Tip: Some letters like G appear same in water image
PYQ 5. A train number "12345" appears in water reflection. What is seen? [RPF SI 2019]
Answer: 54321 with flipped digits
Solution: Reverse order: 54321, then flip each digit vertically: 5→5, 4→4, 3→Ɛ, 2→⅋, 1→1
Exam Tip: In water image, reverse the sequence first, then flip each character
Speed Tricks & Shortcuts
| Situation | Shortcut | Example |
|---|---|---|
| Mirror Clock Time | 12:00 - given time | 4:30 → 7:30 |
| Letters same in mirror | Remember BCDEHIKOX | B→B, C→C, D→D |
| Letters same in water | Remember AHMOTUVWXY | A→A, H→H, M→M |
| Quick mirror check | Write on hand, use phone camera | “TRAIN” → “ИIΛЯT” |
| Water image of numbers | Reverse + flip vertically | “123” → “Ɛ⅋1” |
Common Mistakes to Avoid
| Mistake | Why Students Make It | Correct Approach |
|---|---|---|
| Confusing mirror vs water | Both involve flipping | Mirror = horizontal flip, Water = vertical flip |
| Forgetting to reverse string | Focus only on character flip | Always reverse order first, then flip characters |
| Clock mirror error | Using 6:00 instead of 12:00 | Use 12:00 or 24:00 as reference point |
| Assuming all numbers change | Thinking 0,1,8 also change | Remember 0,1,8 remain same in mirror |
| Ignoring symbol symmetry | Treating all symbols same | ★,⚠,● usually remain unchanged |
Quick Revision Flashcards
| Front (Question/Term) | Back (Answer) |
|---|---|
| Mirror image of A | Λ |
| Water image of M | M |
| Numbers same in mirror | 0, 1, 8 |
| Mirror time formula | 12:00 - given time |
| Letters same in water | A, H, M, O, T, U, V, W, X, Y |
| Mirror of “TRAIN” | ИIΛЯT |
| Water of “STATION” | NOITA⊥S |
| Combined transformation order | Mirror first, then water |
| Platform sign mirror | Reverse + character flip |
| Emergency symbols in mirror | Usually remain same |
Topic Connections
- Direct Link: Alphabet Test - Letter recognition and symmetry concepts
- Combined Questions: Often asked with Direction Sense (train directions in reflections)
- Foundation For: Figure Counting - Understanding symmetry helps in complex figure problems
- Exam Strategy: 2-3 questions guaranteed in every RRB exam, easiest 2 marks if concepts clear
BETA
