Video summary

😳 Sahil Sir Reveals 🔥 Railway Maths Latest Pattern Questions for 2026 Exams 🚆 Must Watch

Main summary

Key takeaways

Educational

Main Ideas / Lessons Conveyed

  • Session purpose: The speaker shares the latest Railway Group D (2026) pattern questions, focusing mainly on:

    • Math/coding-style shortcut methods
    • Exam-relevant formulas

  • Study advice + engagement tactics:

    • Students should study with full concentration and avoid distractions.
    • The speaker claims the comment section is off on his “planet,” so students should focus on learning.

  • Exam prep strategy:

    • Use a topic-wise current affairs plan (running daily on the app).
    • Do revision close to the exam.
    • Mentions an “exclusive offer” on an educational app for Group D learners, including:
      • deadlines
      • multiple batch options

Methodology / Instruction-like Content

A) Cuboid / Geometry Problems (Formulas + Shortcuts)

  • Costing-style “digging a pit” approach:

    1. Convert to volume first:
      • Volume of a cuboid = length × width × height
    2. Then apply the rate mentioned (₹15 per metre-related unit is referenced), and compute accordingly (speaker’s effective method multiplies length × width × height, then applies 15).

  • Total surface area of a cuboid:

    • Total surface area = 2(lw + wh + hl)
    • Expanded as:
      • 2 × (length × width) + 2 × (width × height) + 2 × (height × length)

  • Curved surface area / “four walls”:

    • Curved surface area concept used as: 2 × height × (length + width)

  • Space diagonal inside a cuboid:

    • Diagonal length = √(l² + w² + h²)

  • Algebraic identity (diagonal-related relationships):

    • Speaker discusses relationships derived via algebraic expansion that connect edge sums/surface area/diagonal-related terms.

  • Inner vs outer surface area for boxes with thickness (closed vs open):

    • Closed box with lid:
      • Inner dimensions reduce by 2W in length/width and by 2W in height (both sides adjusted).
    • Open box:
      • Inner dimensions reduce differently—only one side is subtracted in the opening direction.
      • Height reduction by W instead of 2W.
    • Key instruction: Determine whether the top is closed or open, then adjust dimensions before computing surfaces.

B) Average / Replacement Problems (Wordings → Arithmetic Rule)

  • Replacement idea:

    • Example concept: “A group replaces one person” and the average changes for a group of six.

  • Rule used by speaker:

    • If the average changes by an increment, then:
      • New person’s weight = old person’s weight + (change per person × number involved)
    • Example outcome mentioned:
      • Average increases by 2 kg
      • New person weight computed as 72 + 12 = 84 kg

C) Discounts / Successive Discounts

  • Successive discounts:

    • If 4% discount then 25% discount are applied successively:
      • Sold price = Marked price × (1 − 0.04) × (1 − 0.25)

  • Cash discount emphasis:

    • The speaker repeatedly stresses the wording of “cash payment discount”, since discounts may be interpreted as successive rates.

  • Shortcut framing:

    • Percent discounts are converted into remaining multipliers (e.g., 96% after 4%, then apply further discount).

D) Quadratic Equations with Irrational Roots (Conjugate Idea)

  • If one root is irrational, the other root is its conjugate (speaker references it as “jugate”).
  • Use the quadratic structure:
    • x² − (sum of roots)x + (product of roots)
  • Compute sum of roots and product of roots from the given expression to simplify.

E) Ratios with Weighted Averages (Multiple Shops / Mixed Items)

  • Weighted average method:
    • For books/items from two shops (or mixtures), use quantity as weights (e.g., number of books).
  • If one quantity is unknown:
    • Set up equations using ratios and unit prices.
  • JSM method (as referenced):
    • Choose the smaller base and scale the other side proportionally using the ratio units.

F) Loss–Profit / Ratio Method

  • Use CP–SP relationships with percentages:
    • Loss of p% ⇒ SP = CP × (1 − p/100)
    • Profit of q% ⇒ SP = CP × (1 + q/100)
  • Then compare CP ratios when SP is the same.

G) Deviation Method for Average After Removing Numbers

  • Problem style:
    • “Average of 36 numbers is 45. Two numbers are removed. Find average of remaining.”
  • Method 1:
    • Total = 36 × 45
    • Subtract removed sum
    • Divide by remaining count
  • Method 2 (deviation concept):
    • If one removed number is below average and the other is above average by equal deviation:
      • loss and gain cancel in total deviation
      • average stays balanced
  • Instruction:
    • Check whether removed values’ deviations net to zero relative to the original mean.

H) Work and Time / Efficiencies (Combined Work)

  • Work rates:
    • Man completes work in 10 days ⇒ capacity = 1/10 per day
    • Woman completes work in 8 days ⇒ capacity = 1/8 per day
  • Combined completion:
    • Add capacities
    • Invert to get days
  • Speaker also uses a scaling idea:
    • Assume a convenient total (e.g., 40 units) and compute effective efficiency.

I) Speed in Upstream/Downstream (Boat in Current)

  • Let:
    • Boat speed in still water = u
    • Current speed = v
  • Effective speeds:
    • Upstream = u − v
    • Downstream = u + v
  • Use given times:
    • Distance = speed × time in both directions
  • Solve for v (current speed); speaker’s example yields v = 10).

J) Traffic Signals / Changing Lights (LCM/HCF Type)

  • Rule:
    • Traffic signal changing lights questions are LCM/HCF based.
  • Instruction:
    • Find LCM of cycle durations.
    • Convert seconds to minutes if needed.

K) Statistics Formulas (Mean / Median / Mode for Distributions)

  • Relation stated:
    • Mode = 3×Median − 2×Mean
  • Instruction approach:
    • Identify median and mean from given data/distribution
    • Substitute into the formula to get mode
    • Speaker notes a correction after an earlier arithmetic error.

Examples of Question Topics Shown (High-Level)

  • Cuboid pit problems: volume, surface area, diagonal
  • Open vs closed boxes (inner vs outer surfaces)
  • Replacement/average increase problems
  • Successive discounts (selling price)
  • Quadratics with irrational roots using conjugate
  • Weighted average from two shops / mixed items
  • Time-rate problems (tanks with leak mentioned as a topic)
  • Ratio/mixture problems (e.g., milk–water style)
  • Deviation-based average after removing values
  • Boat speed in current (upstream/downstream)
  • Work completion by man/woman efficiencies
  • Traffic signals (LCM-based)
  • Statistics: mean/median/mode

Speakers / Sources Featured

  • Speaker/Host: “Sahil Sir” (presented as the instructor throughout)
  • Mentioned educational sources/platforms:
    • Dekho Bhaiya application
    • “target batch / foundation / combined batch”
    • Telegram / PDF / current affairs references (no other named instructor identified beyond Sahil Sir)

Original video