Question:

Let $S =\{1,2,3,5,7,10,11\}$ The number of non-empty subsets of $S$ that have the sum of all elements a multiple of 3 , is _____

Updated On: Dec 8, 2024
Hide Solution
collegedunia
Verified By Collegedunia

Correct Answer: 43

Solution and Explanation

The correct answer is 43.
Elements of the type
Elements of the type
Elements of the type
Subsets containing one element
Subsets containing two elements

Subsets containing three elements

Subsets containing four elements

Subsets containing five elements

Subsets containing six elements
Subsets containing seven elements
Was this answer helpful?
18
22

Questions Asked in JEE Main exam

View More Questions

Concepts Used:

Relations

A relation in mathematics defines the relationship between two different sets of information. If two sets are considered, the relation between them will be established if there is a connection between the elements of two or more non-empty sets. Therefore, we can say, ‘A set of ordered pairs is defined as a relation.’

Read Also: Relation and Function

Types of Relations:

There are 8 main types of relations which are:

  1. Empty Relation - An empty relation is one in which there is no relation between any elements of a set.
  2. Universal Relation - A universal is a type of relation in which every element of a set is related to each other. Now one of the universal relations will be R = {x, y} where, |x – y| ≥ 0. For universal relation, R = A × A
  3. Identity Relation - In an identity relation, every element of a set is related to itself only. For example, in a set A = {a, b, c}, the identity relation will be I = {a, a}, {b, b}, {c, c}.
  4. Inverse Relation - It is seen when a set has elements which are inverse pairs of another set. For example if set A = {(a, b), (c, d)}, then inverse relation will be R-1 = {(b, a), (d, c)}.
  5. Reflexive Relation - If every element of set A maps for itself, then set A is known as a reflexive relation.It is represented as a∈ A, (a,a) ∈ R.
  6. Symmetric Relation - A relation R on a set A is known as asymmetric relation if (a, b) ∈R then (b, a) ∈R , such that for all a and b ∈A.
  7. Transitive Relation - For transitive relation, if (x, y) ∈ R, (y, z) ∈ R, then (x, z) ∈ R. For a transitive relation, aRb and bRc ⇒ aRc ∀ a, b, c ∈ A
  8. Equivalence Relation - If a relation is reflexive, symmetric and transitive at the same time it is known as an equivalence relation.

Representation of Relations:

There are two ways by which a relation can be represented-

  1. Roster method
  2. Set-builder method

The roster form and set-builder for for a set integers lying between -2 and 3 will be-

Roster form

I= {-1,0,1,2}

Set-builder form

I= {x:x∈I,-2<x<3}