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\} $ |
Since in $(d),$ there are $9$ letters in the word $PRINCIPAL$ and two letters $P$ and $I$ are repeated, so
$(i)$ matches $(d).$ Similarly, $(ii)$ matches $(c)$ as $x+1=1$ implies $x=0 .$ Also, $1,2,3,6,9,18$ are all divisors of $18$ and so $(iii)$ matches $(a).$ Finally, $x^{2}-9=0$ implies $x=3,-3$ and so $(iv)$ matches $(b).$
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 $A$ ?
Write the following sets in roster form :
$A = \{ x:x$ is an integer and $ - 3 < x < 7\} $
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{1,2,5\}\subset A$
Make correct statements by filling in the symbols $\subset$ or $ \not\subset $ in the blank spaces:
$\{ x:x$ is a circlein the plane $\} \ldots \{ x:x$ is a circle in thesame plane with radius $1$ unit $\} $
Examine whether the following statements are true or false :
$\{ x:x$ is an even natural number less than $6\} \subset \{ x:x$ is a natural mumber which divide $36\} $