Question

Write the cardinal number of the set A = {x : x = 5y, y ∈W, 2 <=y < 6}

Answer 1

Answer:

The answer is 4

Step-by-step explanation:

Given $y$ is whole number and $2\le y<6$

so values of $y$ are $2,3,4,5$

And since $x=5y$, so values of $x$ are $10,15,20,25$

Therefore

         $A=\{10,15,20,25\}$

So the cardinal number of A is 4 (as A has four elements)