Join WhatsApp Icon JEE WhatsApp Group
Question 80

Let $$N$$ denote the sum of the numbers obtained when two dice are rolled. If the probability that $$2^N < N!$$ is $$\frac{m}{n}$$, where $$m$$ and $$n$$ are coprime, $$4m - 3n$$ is equal to

1. Analyze the condition $$2^N < N!$$

For the sum $$N$$ of two dice, $$N$$ can range from $$2$$ to $$12$$.

  • If $$N=2$$: $$2^2 = 4$$, $$2! = 2 \implies 4 \nless 2$$ (False)
  • If $$N=3$$: $$2^3 = 8$$, $$3! = 6 \implies 8 \nless 6$$ (False)
  • If $$N=4$$: $$2^4 = 16$$, $$4! = 24 \implies 16 < 24$$ (True)

The condition $$2^N < N!$$ is true for all $$N \geq 4$$.

2. Calculate the Probability

The total number of outcomes when rolling two dice is $$36$$.

We need $$P(N \geq 4)$$, which is easier to calculate as $$1 - P(N < 4)$$.

  • Outcomes for $$N=2$$: $$(1,1)$$ — (1 outcome)
  • Outcomes for $$N=3$$: $$(1,2), (2,1)$$ — (2 outcomes)

Total outcomes for $$N < 4$$ is $$1 + 2 = 3$$.

$$P(N \geq 4) = 1 - \frac{3}{36} = 1 - \frac{1}{12} = \frac{11}{12}$$

Here, $$m = 11$$ and $$n = 12$$ (they are coprime).

3. Final Calculation

Substitute $$m$$ and $$n$$ into the expression $$4m - 3n$$:

$$4(11) - 3(12) = 44 - 36 = \mathbf{8}$$

Correct Option: (D)

Get AI Help

Video Solution

video

Create a FREE account and get:

  • Free JEE Mains Previous Papers PDF
  • Take JEE Mains paper tests

JEE Quant Questions | JEE Quantitative Ability

JEE DILR Questions | LRDI Questions For JEE

JEE Verbal Ability Questions | VARC Questions For JEE

Free JEE Topicwise Questions

JEE Rotational MotionJEE Units & MeasurementsJEE Atomic StructureJEE GravitationJEE Periodic Table & PeriodicityJEE StatisticsJEE Inverse Trigonometric FunctionsJEE Magnetism & Magnetic MaterialsJEE Sequences & SeriesJEE MatricesJEE Alternating CurrentsJEE Carboxylic AcidsJEE Permutations & CombinationsJEE Work, Energy & PowerJEE Electromagnetic InductionJEE Electronic DevicesJEE d and f-Block ElementsJEE Chemical KineticsJEE Heat TransferJEE Three Dimensional GeometryJEE Magnetic Effects of CurrentJEE Hydrocarbons - AromaticJEE Electromagnetic WavesJEE Aldehydes & KetonesJEE Hydrocarbons - AlkanesJEE Applications of DerivativesJEE EquilibriumJEE Indefinite IntegrationJEE Chemical ThermodynamicsJEE ElectrochemistryJEE ProbabilityJEE BiomoleculesJEE Continuity & DifferentiabilityJEE Kinetic Theory of GasesJEE Vector AlgebraJEE Hydrocarbons - AlkynesJEE Differential EquationsJEE Current & ResistanceJEE Straight LinesJEE WavesJEE Redox ReactionsJEE Hydrocarbons - AlkenesJEE DeterminantsJEE SolutionsJEE Ray OpticsJEE Dual Nature of Matter & RadiationJEE Chemical Bonding & Molecular StructureJEE Complex NumbersJEE Sets, Relations & FunctionsJEE Electric Charges & FieldsJEE Laws of MotionJEE Fluid MechanicsJEE Basic Concepts in ChemistryJEE Trigonometric FunctionsJEE LimitsJEE Laws of ThermodynamicsJEE Kinematics - 2D MotionJEE p-Block Elements (Groups 13-18)JEE Simple Harmonic MotionJEE Electric Potential & CapacitanceJEE Coordination CompoundsJEE JEE 2D GeometryJEE CirclesJEE Definite IntegrationJEE EMF & Circuit AnalysisJEE Surface TensionJEE Atoms & NucleiJEE Laboratory Experiments - XIJEE Number SystemJEE Basic Principles of Organic ChemistryJEE Wave OpticsJEE Quadratic EquationsJEE Alcohols, Phenols & EthersJEE Organic Compounds with HalogensJEE DifferentiationJEE Conic SectionsJEE Nitrogen-Containing CompoundsJEE ElasticityJEE Practical Organic ChemistryJEE Kinematics - 1D MotionJEE Purification & CharacterisationJEE Binomial Theorem
Ask AI