📘 BANK EXAM SPEED MATHS – PAGE 17

🔹 Permutation & Combination Tricks

Permutation and combination questions test logical arrangement and selection skills. Shortcut understanding of formulas is key.

✅ Trick 1: Permutation Formula

nPr = n! / (n − r)!

Example: 5P2

• 5 × 4 = 20

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✅ Trick 2: Combination Formula

nCr = n! / [r!(n − r)!]

Example: 5C2

• = (5×4) / (2×1) = 10

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🔹 Probability Tricks

✅ Trick 3: Basic Probability

Formula: Probability = Favorable / Total

Example: Probability of getting head in coin toss

• = 1/2

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✅ Trick 4: Complement Rule

P(Not A) = 1 − P(A)

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🔹 Data Sufficiency Tricks

Data sufficiency questions test whether given data is enough to answer the question.

✅ Trick 5: Solve Statements Individually

• Check Statement 1 alone
• Check Statement 2 alone
• Combine only if needed

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✅ Trick 6: Avoid Full Calculation

Only check sufficiency, not exact answer.

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🔹 Tough Practice Questions

1. Find 6P2
2. Find 6C3
3. Probability of getting 3 in a dice
4. Probability of not getting head in coin toss
5. Is x > 5?
   (1) x = 6
   (2) x² = 36

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🔹 Quick Answers

• 1. 30
• 2. 20
• 3. 1/6
• 4. 1/2
• 5. Statement 1 alone sufficient

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🔹 Exam Tips

✔ Memorize basic formulas of permutation and combination
✔ Use logical thinking in probability questions
✔ Do not solve fully in data sufficiency
✔ Practice different patterns regularly

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