Question

write the given set in Rostey form and also to write the cardinal number of the set
{x/x = 3n,n€N, n<6}​

Answer 1

Step-by-step explanation:

x=3n

where n is a natural number and n<8

So, n can be any digit from 1,2,3,4,5,6,7

So, in roster form

A={3,6,9,12,15,18,21}

Cardinal number = no. of distinct elements in the Set=7