
The number of numbers divisible by 3 that can be formed by four different even digits is
(a) 18
(b) 36
(c) 0
(d) None of these
Answer
168.9k+ views
Hint: For finding the number of numbers divisible by 3 we use the permutation concept. First, we must know the divisibility rule of 3 which states that a number is divisible by 3 only when the sum of individual digits is divisible by 3. By using this we can easily solve our problem.
Complete step-by-step answer:
According to our problem, even digits can be stated as 0, 2, 4, 6, 8.
As the divisibility rule of 3 states that a number is divisible by 3 only when the sum of individual digits is divisible by 3. So, the 4 different even digit numbers are divisible by 3 = set of (2, 4, 6, 0) and (8, 6, 4, 0).
So, the number of combinations possible = $4!$.
But, if 0 occurs at first place then the number is not four digits. So, cases for 0 at first place = $3!$.
So, total valid combinations = $4!-3!=18$.
But there are two possible sets, so multiplying the obtained result by 2 we get total valid combinations as = $18\times 2=36$.
Therefore, option (b) is correct.
Note: The key concept of solving this problem is the knowledge of permutations and divisibility rule for 3. Once the total number of cases are obtained by using the given criteria, then by using permutation the final result can be evaluated without any error.
Complete step-by-step answer:
According to our problem, even digits can be stated as 0, 2, 4, 6, 8.
As the divisibility rule of 3 states that a number is divisible by 3 only when the sum of individual digits is divisible by 3. So, the 4 different even digit numbers are divisible by 3 = set of (2, 4, 6, 0) and (8, 6, 4, 0).
So, the number of combinations possible = $4!$.
But, if 0 occurs at first place then the number is not four digits. So, cases for 0 at first place = $3!$.
So, total valid combinations = $4!-3!=18$.
But there are two possible sets, so multiplying the obtained result by 2 we get total valid combinations as = $18\times 2=36$.
Therefore, option (b) is correct.
Note: The key concept of solving this problem is the knowledge of permutations and divisibility rule for 3. Once the total number of cases are obtained by using the given criteria, then by using permutation the final result can be evaluated without any error.
Recently Updated Pages
P Block Elements: Definition, Groups, Trends & Properties for JEE/NEET

Order of Reaction in Chemistry: Definition, Formula & Examples

Molarity vs Molality: Definitions, Formulas & Key Differences

Preparation of Hydrogen Gas: Methods & Uses Explained

Polymers in Chemistry: Definition, Types, Examples & Uses

Hydrocarbons: Types, Formula, Structure & Examples Explained

Trending doubts
JEE Main 2025 Session 2: Application Form (Out), Exam Dates (Released), Eligibility, & More

Displacement-Time Graph and Velocity-Time Graph for JEE

Atomic Structure - Electrons, Protons, Neutrons and Atomic Models

JEE Main 2025: Derivation of Equation of Trajectory in Physics

Instantaneous Velocity - Formula based Examples for JEE

Ideal and Non-Ideal Solutions Raoult's Law - JEE

Other Pages
JEE Advanced Marks vs Ranks 2025: Understanding Category-wise Qualifying Marks and Previous Year Cut-offs

NCERT Solutions for Class 11 Maths Chapter 4 Complex Numbers and Quadratic Equations

JEE Advanced Weightage 2025 Chapter-Wise for Physics, Maths and Chemistry

Learn About Angle Of Deviation In Prism: JEE Main Physics 2025

JEE Main 2025: Conversion of Galvanometer Into Ammeter And Voltmeter in Physics

Electric Field Due to Uniformly Charged Ring for JEE Main 2025 - Formula and Derivation
