🎙 Teacher-Style Introduction

Percentage chapter DP Constable exam mein 3–4 number ka stable scoring topic hai. Discount, profit, loss, marks, population growth— sab percentage ke base par aate hain. Agar aap is chapter ko master kar lete ho toh arithmetic 50% solve ho jata hai.

Is chapter mein basic % to fraction conversion, increase/decrease %, aur simple applications aate hain.

📘 Important Formulas / महत्वपूर्ण सूत्र

• Percentage = (Value / Total) × 100
• Value = (Percentage × Total) / 100
• Increase% = ((New − Old) / Old) × 100
• Decrease% = ((Old − New) / Old) × 100
• a% of b = (a × b) / 100

• प्रतिशत = (मान / कुल) × 100
• मान = (प्रतिशत × कुल) / 100
• वृद्धि% = (नया − पुराना) / पुराना × 100
• कमी% = (पुराना − नया) / पुराना × 100
• a% का b = (a × b) / 100

⚡ Tricks & Shortcuts / ट्रिक्स व शॉर्टकट

• 1% = 1/100 → fastest conversion
• 50% = 1/2, 25% = 1/4, 20% = 1/5, 12.5% = 1/8
• Agar % bade numbers par ho → mentally fraction convert karo
• DP exam me decimal % bohot simple hote hain (0.5% etc)
• Increase/decrease me sabse pehle difference nikaalo, phir % base use karo

🎯 Exam Angle (Delhi Police)

• 3–4 questions har saal CRPF/DP exams me percentage se
• Mostly: % of number, increase/decrease, marks, ratio-% relation
• No lengthy calculations—paper ka easiest scoring section

✔ Solved Examples / हल प्रश्न

Example 1: Find 20% of 150
Solution: 20% = 20/100 = 0.2 → 0.2 × 150 = 30

Example 2: 25% of 200 = ?
Solution: 25% = 1/4 → 200/4 = 50

Example 3: If price increases from 100 to 120, find increase%.
Solution: Increase = 20 → (20/100)×100 = 20%

Example 4: A student scores 45 out of 60. Find percentage.
Solution: (45/60)×100 = 75%

Example 5: Decrease from 500 to 450 = ?%
Solution: Decrease = 50 → (50/500)×100 = 10%

Example 6: What is 12.5% of 80?
Solution: 12.5% = 1/8 → 80/8 = 10

Example 7: Find 40% of 250.
Solution: 40/100 × 250 = 100

Example 8: 60% of 90 = ?
Solution: 0.6 × 90 = 54

✔ MCQs (Delhi Police Pattern)

1. 20% of 80 = ?
   Ans: 16
2. 25% of 120 = ?
   Ans: 30
3. A price rises from 200 to 240. Increase%=?
   Ans: 20%
4. 40 is what % of 200?
   Ans: 20%
5. 45% of 60 = ?
   Ans: 27
6. 10% of 350 = ?
   Ans: 35
7. 30% of 90 = ?
   Ans: 27
8. 80% of 50 = ?
   Ans: 40
9. 12.5% of 64 = ?
   Ans: 8
10. Find % decrease from 600 → 540
    Ans: 10%
11. 15% of 300 = ?
    Ans: 45
12. 5% of 500 = ?
    Ans: 25

💡 Motivation: Jo student percentage strong kar leta hai, uska Arithmetic automatically 50% strong ho jata hai. Keep going—success near hai!