JEE Main · Maths · Probability
Theorem of Total Probability
JEE Main asked Theorem of Total Probability 3 times in 3 of the 108 shifts Lumi analysed, in 2020, 2023 and 2026. It belongs to Bayes' Theorem, in Probability (Maths). The longest wait between two years asking it was 3 years.
Updated 2026-10-24
- Times asked
- 3
- in 3 shifts
- Years
- 3 of 8
- First asked
- 2020
- last in 2026
- Pattern
- Frequent
- across the analysed shifts
Questions on this idea a shift, by year
2017–2026. Asked in 2020, 2023 and 2026. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Maths questions.
Raw count: 2017: 0 in 1 shift · 2020: 1 in 12 shifts · 2021: 0 in 24 shifts · 2022: 0 in 24 shifts · 2023: 1 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 1 in 9 shifts.
Shift by shift
Each square is one analysed shift, in date order. Open a filled one for that paper.
How JEE Main framed it
Single correct is the usual form. Skill tested: multi-step.
- Total probability with biased coin
- Bayes posterior with box selection
Difficulty
Every question was multiple choice.
Every question
All 3 questions
From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.
- 6 Apr 2026, Shift 1 · Q10A bag contains coins N fair coins, and one coin with 'Head' on both sides. A coin is selected at random and tossed.…EasySingle correct
- 15 Apr 2023, Shift 1 · Q18A bag contains 6 white and 4 black balls. A die is rolled once and the number of balls equal to the number obtained on the die are drawn…MediumSingle correct
- 2 Sep 2020, Shift 1 · Q68Box I contains 30 cards numbered 1 to 30 and Box II contains 20 cards numbered 31 to 50. A box is selected at random and a card is drawn…MediumSingle correct
Shifts: 2 Sep 2020, Shift 1, 15 Apr 2023, Shift 1, 6 Apr 2026, Shift 1.
Same topic
Other ideas in Bayes' Theorem
Bayes' Theorem has 6 ideas JEE Main has asked; 3 of them came up in more than one question.
- Bayes' Theorem Application9× · 2026
- Implicit Equally Likely Priors2× · 2024
- Biased vs Unbiased Instrument Selectiononce · 2025
- Missing or Lost Card Scenariosonce · 2025
- Urn and Ball Transfer Problemsonce · 2022