Question

Let A = {months of the year with less than 31 days}
Work out n(A)

Answer 1

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Answer:

$\boxed{\textsf{ The number of elements of set A is \textbf{5} .}}$

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Step-by-step explanation:

A set is given to us , and we need to find the number of elements in the set. The given set is ,

$\sf\red{\dashrightarrow} A = \{ \textsf{ Months of the year with less than 31 days}\}$

There are in total of 12 months . Out of which , February , April , June , September and November have 30 or 28 ( Feb) days. These months satisfy the Condition of the set . And these are 5 in number.

Therefore the number of elements in set A is 5 .

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$\qquad\qquad\qquad\underline{\red{\sf More \ To \ Know :- }}$

We can represent sets in two forms ,

• Roster Form
• Set - Builder Form

➳ Roster Form :-

• In this form , all elements of a set are listed , and are seperated by commas , within curly ( {} ) brackets .
• For ex - The set of days of week = { S , M , T , W , Th , F , Sa }

➳ Set Builder Notation :-

• In this form , all elements of a set posses a single Common property , which is not possessed by any element outside the set.
• Set of days can be written as , D = { x : x is a day in week } .

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