Kundali IQ
Menu ☰
SSC Maths AcademyHomeSchool 6–12Free notesExplore allMy study planSearchExamsTeachers & parentsPricingFAQOpen appGet it on Google Play

Home › Exam notes › Railway RRB › Percentage

Percentage

Quantitative Aptitude / DI · Speed Calculation

Useful for: Railway RRB, IBPS Banking, CTET, OTET, OSSTET, UGC NET, OSSC RHT — Regular High School Teacher, UPSC NDA/NA

and 21 more exams

CSIR NET, CTSA / STSS, Central Univ./IIT/NIT Faculty, Junior Teacher, OAVS, OPSC Assistant Professor, OPSC PGT, OSEPA Primary Teacher / JT Category-I, OSEPA Upper Primary — Science, OSSC Mathematics, OSSC Teacher Readiness, OSSSC Govt Physical Education Teacher (PET), OSSSC Govt TGT Arts, OSSSC Govt TGT Science — CBZ, OSSSC Govt TGT Science — PCM, Sainik Schools, Special OTET, SSB Lecturer / PGT, SSB Lecturer (Degree Colleges), SSB School Teachers, SSB TGT PCM

हिंदी में पढ़ें

Overview

Percentage means "per hundred"; fast fraction–percentage conversion and base-change logic solve most items.

Key points

  • X% of y = y% of x (e.g. 8% of 50 = 50% of 8 = 4).
  • Key conversions: 1/8 = 12.5%, 1/6 = 16.67%, 1/7 ≈ 14.29%, 1/9 = 11.11%, 1/11 = 9.09%, 1/12 = 8.33%.
  • If A is r% more than B, B is r/(100 + r) × 100% less than A.
  • If price rises by r%, consumption must fall by r/(100 + r) × 100% to keep expenditure unchanged.
  • Percentage change = (change ÷ original) × 100.

Explanation

  • Always identify the base: "more than B" means B is the base.
  • Percentage points differ from percent: 10% to 12% is a rise of 2 percentage points but 20%.
  • In elections: votes for winner − loser = given margin; set up the equation on total valid votes.
  • Use fraction equivalents to avoid long multiplication.

Step by step

  1. Find the base.
  2. Convert % to a fraction.
  3. Compute and check that the result is reasonable.

Examples

  • 40% of 250 = 2/5 × 250 = 100.
  • A’s salary is 20% more than B’s. B’s salary is less than A’s by 20/120 × 100 = 16.67%.
  • Price of sugar rises 25%. To keep spending the same, consumption must fall by 25/125 × 100 = 20%.

Traps and advanced points

  • Trap: Using the wrong base (answering 20% instead of 16.67% above).
  • Trap: Adding percentages of different bases directly.
  • Trap: Confusing percentage points with percent change.

Quick revision

  • R% more ↔ r/(100+r) less.
  • Learn 1/2 to 1/12 as percentages.
  • Base = "than ___".

Practice MCQs

  1. 30% of a number is 681. What is the number?

    1. 2043
    2. 2724
    3. 2497
    4. 2270

    Read chapter notes · Similar questions

    Show answer

    Answer: (d) 2270. Number = 681×100/30.

  2. 40% of a number is 460. What is the number?

    1. 1265
    2. 1150
    3. 1035
    4. 1380

    Read chapter notes · Similar questions

    Show answer

    Answer: (b) 1150. Number = 460×100/40.

  3. 60% of a number is 555. What is the number?

    1. 1017.5
    2. 925
    3. 832.5
    4. 1110

    Read chapter notes · Similar questions

    Show answer

    Answer: (b) 925. Number = 555×100/60.

  4. 75% of a number is 564. What is the number?

    1. 902.4
    2. 827.2
    3. 752
    4. 676.8

    Read chapter notes · Similar questions

    Show answer

    Answer: (c) 752. Number = 564×100/75.

  5. 12% of a number is 501. What is the number?

    1. 3757.5
    2. 4592.5
    3. 4175
    4. 5010

    Read chapter notes · Similar questions

    Show answer

    Answer: (c) 4175. Number = 501×100/12.

  6. 75% of a number is 420. What is the number?

    1. 616
    2. 560
    3. 504
    4. 672

    Read chapter notes · Similar questions

    Show answer

    Answer: (b) 560. Number = 420×100/75.

  7. 30% of a number is 825. What is the number?

    1. 3300
    2. 2475
    3. 2750
    4. 3025

    Read chapter notes · Similar questions

    Show answer

    Answer: (c) 2750. Number = 825×100/30.

  8. 20% of a number is 125. What is the number?

    1. 687.5
    2. 750
    3. 562.5
    4. 625

    Read chapter notes · Similar questions

    Show answer

    Answer: (d) 625. Number = 125×100/20.

  9. 20% of a number is 149. What is the number?

    1. 819.5
    2. 670.5
    3. 745
    4. 894

    Read chapter notes · Similar questions

    Show answer

    Answer: (c) 745. Number = 149×100/20.

  10. 15% of a number is 798. What is the number?

    1. 4788
    2. 5320
    3. 6384
    4. 5852

    Read chapter notes · Similar questions

    Show answer

    Answer: (b) 5320. Number = 798×100/15.

  11. 15% of a number is 654. What is the number?

    1. 4796
    2. 4360
    3. 3924
    4. 5232

    Read chapter notes · Similar questions

    Show answer

    Answer: (b) 4360. Number = 654×100/15.

  12. 25% of a number is 104. What is the number?

    1. 416
    2. 374.4
    3. 457.6
    4. 499.2

    Read chapter notes · Similar questions

    Show answer

    Answer: (a) 416. Number = 104×100/25.

  13. 20% of a number is 221. What is the number?

    1. 994.5
    2. 1215.5
    3. 1326
    4. 1105

    Read chapter notes · Similar questions

    Show answer

    Answer: (d) 1105. Number = 221×100/20.

  14. 25% of a number is 80. What is the number?

    1. 352
    2. 320
    3. 384
    4. 288

    Read chapter notes · Similar questions

    Show answer

    Answer: (b) 320. Number = 80×100/25.

  15. 15% of a number is 870. What is the number?

    1. 5800
    2. 6960
    3. 5220
    4. 6380

    Read chapter notes · Similar questions

    Show answer

    Answer: (a) 5800. Number = 870×100/15.

More topics in this chapter

Notes and questions are written by Kundali IQ for practice. They are not official papers; always check the latest official notification for the syllabus and pattern.