Lecture Notes: GATE Preparation - General Aptitude (Clocks and More)

Introduction

• Focus on GATE 2025 preparation.
• Addressing preparation doubts and queries.
• Clarification through faculty is essential.
• Today's topic: Clocks.

Lecture Series Overview

• General Aptitude: Essential for GATE (15 marks).
• Divided into four sections:
  1. Quantitative Aptitude (majority questions from this part).
  2. Analytical Aptitude (Reasoning).
  3. Spatial Aptitude (Non-verbal reasoning/figurative aptitude).
  4. Verbal Aptitude (English).

Class Schedule

• Monday to Friday: Lectures from 9:00 PM onward.
• Saturday & Sunday: Practice days, with assignments given in sessions.
• Various important topics covered, including:
  • *Clocks
  • Averages & Ages
  • Percentages
  • Profit & Loss
  • Calendar
  • Algebra & Square Roots
  • Mensuration (2D & 3D)
  • Geometry
  • Interest calculations
  • Blood Relations
  • Coding-Decoding
  • Directions
  • Arrangements & Ranking
  • Problem Solving
  • Syllogisms*

Clocks: Detailed Breakdown

• Types of Hands on a Clock: Minimum of Two Hands: Hour Hand (HH) & Minute Hand (MH).
• Ignoring second hand and special hands (alarm, temperature, etc.) for these concepts.
• Concept of Relative Speed: Key to solving clock problems.
  • Hands move in the same direction (clockwise), so relative speed = subtraction of speeds.
  • Speeds: HH = 0.5° per minute, MH = 6° per minute.
  • Relative Speed: 5.5° per minute.

Key Types of Questions

1. **Time Given, Find the Angle:
   • Process: Calculate the angle formed by HH and MH.
     • Example: 4:00 -> 120° (4 * 30°).
     • Random time: Calculate base angle and movement of MH using relative speed.
2. **Angle Given, Find the Time:
   • Process: Use given angle to backtrack time.
     • Example: 2:00 PM to 3:00 PM, find when the angle is 90°. Perform calculations and consider both possible angles.
3. **Gain & Lose Time:
   • Clocks gaining/losing time per hour. Calculate the actual or shown time based on described gain/loss.
     • Example: Clock gains 5 minutes/hour, set correctly at 8:00 AM -> 2:00 PM shows 2:30 PM.***

Assignments/Examples

• Clock Problems: Real-world GATE style questions for homework.
• Calculation Examples: Provided for practice and better understanding.

Conclusion

• Recap of lecture highlights.
• Prep strategy: Clarity in concepts and regular practice.
• Next session: Further problem-solving and advanced clock problems.

End Notes

• Importance of interaction and clarifying doubts in class.
• Encourage practice and participation in further classes.