Which of the following are sets ? Justify your answer.
The collection of all the months of a year beginning with the letter $\mathrm{J}.$
Which of the following are sets ? Justify your answer.
The collection of all the months of a year beginning with the letter $\mathrm{J}.$
The collection of all months of a year beginning with the letter $\mathrm{J}$ is a well-defined collection of objects because one can definitely identity a month that belongs to this collection.
Hence, this collection is a set.
Similar Questions
In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.
If $A \subset B$ and $B \in C,$ then $A \in C$
In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.
If $A \subset B$ and $B \in C,$ then $A \in C$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\varnothing \subset A$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\varnothing \subset A$
Write the following intervals in set-builder form :
$\left[ { - 23,5} \right)$
Write the following intervals in set-builder form :
$\left[ { - 23,5} \right)$
Match each of the set on the left described in the roster form with the same set on the right described in the set-builder form:
$(i)$ $\{ P,R,I,N,C,A,L\} $
$(a)$ $\{ x:x$ is a positive integer and is adivisor of $18\} $
$(ii)$ $\{ \,0\,\} $
$(b)$ $\{ x:x$ is an integer and ${x^2} - 9 = 0\} $
$(iii)$ $\{ 1,2,3,6,9,18\} $
$(c)$ $\{ x:x$ is an integer and $x + 1 = 1\} $
$(iv)$ $\{ 3, - 3\} $
$(d)$ $\{ x:x$ is aletter of the word $PRINCIPAL\} $
Match each of the set on the left described in the roster form with the same set on the right described in the set-builder form:
| $(i)$ $\{ P,R,I,N,C,A,L\} $ | $(a)$ $\{ x:x$ is a positive integer and is adivisor of $18\} $ |
| $(ii)$ $\{ \,0\,\} $ | $(b)$ $\{ x:x$ is an integer and ${x^2} - 9 = 0\} $ |
| $(iii)$ $\{ 1,2,3,6,9,18\} $ | $(c)$ $\{ x:x$ is an integer and $x + 1 = 1\} $ |
| $(iv)$ $\{ 3, - 3\} $ | $(d)$ $\{ x:x$ is aletter of the word $PRINCIPAL\} $ |
Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?
Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?
- [KVPY 2012]