Question

Roster form of the following set is : A={x: x ∈ 3N and N<5

Answer 1

Answer:

A = {3,6,9,12}

Step-by-step explanation:

x = 3n

where n is a natural number and n < 5

So, n can be any digit from 1,2,3,4

So, in roster form

A = {3,6,9,12}

Cardinal number = no. of distinct elements in the Set = 4