Placement prep
Aptitude and Reasoning
Quant, probability, puzzles and logical reasoning with shortcuts for placement tests.
- Handwritten-style
- Diagrams and tables
- Worked examples
Who this notebook is for
Students preparing for placement tests and online assessments. It starts from the basics of each topic and teaches the shortcuts that save time in a timed test.
What you will be able to do
- Solve percentage, ratio and profit and loss questions quickly
- Handle time and work, speed and distance and interest questions
- Work out simple probability and counting questions
- Approach puzzles, seating arrangements and blood relation questions step by step
What's inside
Pick a chapter and the notebook opens right there.
- Number Systems & DivisibilityClassification, Divisibility Rules 2–19, Unit Digit Cyclicity ($4k+r$), Trailing Zeros Legendre, Factors Count & Sum, Modulo ArithmeticStart here
- HCF, LCM & Remainder TheoremsEuclidean GCD, Prime Factorization, Fraction LCM/HCF, Bell Tolling Synchrony, Remainder Models (Constant Remainder $R$), Fermat/WilsonStart here
- Percentages & Profit/LossFraction Equivalents, Successive Percentage $a+b+ab/100$, Marked Price & Discounts, Dishonest Shopkeeper False Weights, Speed DrillsStart here
- Simple & Compound InterestSI Linear Growth, CI Compounding Frequencies, Sum Doubling Rule of 72, CI–SI Differences ($2$ & $3$ Years), Installments & EMIsStart here
- Ratios, Mixtures & AlligationCompound Ratios, Mean Proportionals, Direct/Inverse Variations, Cross- Alligation Cheats, Repeated Liquid Dilution FormulaStart here
- Time, Work & CisternsLCM Total Work Units, Men-Days $M_1 D_1 H_1 / W_1$, Work Efficiency Ratios, Negative Work Leaks & Inlets, Alternating Hourly ShiftsStart here
- Boats, Streams & RacesFluid Kinematics ($u=(S_d+S_u)/2$), Moving Escalator Step Invariant, Track Head Starts, Circular Track First Meeting & CoincidenceStart here
- Time, Speed & DistanceConversion 5/18, Harmonic Mean Average Speed, Relative Speed (Trains Crossing Platforms/Moving Men), Late/Early EquationsStart here
- Permutations & CombinationsFundamental Principles of Counting, Linear vs Circular $(n-1)!$, Tie-Together & Gap Methods, Beggar's Method Coins, Repetition DigitsStart here
- Probability & Bayes' TheoremSample Spaces, Conditional Probability $P(A|B)$, Independent Events, Bayes' Theorem Factory Defectives, Binomial DistributionStart here
- Mensuration 2D & 3D GeometryTriangles & Pythagorean Triplets, Circles & Sectors, Prismatic Solids (Cubes/Cylinders), Cones/Spheres, Conservation in MeltingStart here
- Clocks, Calendars & Odd DaysDial Speeds $5.5^{\circ}/\text{min}$, Master Angle $|30H-5.5M|$, Faulty Clocks Drift, Solar Odd Days, Century Codes, Day of Any DateStart here
- Syllogisms & Venn DiagramsPropositions A/E/I/O, Immediate Conversion Rules, Mediate Inferences, 3- Statement Chains, Possibility Testing & Either-Or PairsStart here
- Blood Relations & Family TreesGenerational Tiers, Standard Diagrammatic Syntax, Backward Parsing "Pointing to...", Coded Relations $P+Q*R$, In-Law MatricesStart here
- Direction Sense & Seating8 Compass Points, Pythagorean Displacement, Sunrise/Sunset Shadows, Linear Rows, Circular Inward/Outward Mixed Facing, Square TablesStart here
- Coding-Decoding & SeriesEJOTY & 27-Complements, Shift Ciphers & Transpositions, Difference Pyramids (Tier 1 & 2), Fractional Multipliers, Wrong NumberStart here
- Data Sufficiency & Puzzles1-2-T-E Protocol, Linear Independence Degrees of Freedom, Logical Ordering, Multi-Attribute Grids, Floor & Box StacksStart here
- Top Placement Math ShortcutsVedic Base-100 Multipliers, Instant Cube Roots, High-Yield Traps, Digital Sum Modulo 9, 3-Pass Exam Triage & 108-Page Master SheetStart here
Practice this
Put it to work on LakeBench.
Read the guide first
Short explainers that pair with this notebook.
Common questions
- Is this notebook enough for company aptitude tests?
- It covers the topics those tests repeat. Pair it with timed practice, because speed comes from solving many questions.
- Do I need to be good at maths?
- No. Each chapter starts from the basic idea and builds up, and the shortcuts are shown beside the long method so you can see why they work.
- Can I read a sample before I commit?
- Yes. The contents pages and the first pages of every notebook can be read online, so you can judge the style before going further.
