Question

Find the cardinal number of the following set.

Q = `{y : y = 4/(3"n"), "n" ∈ "N" and 2 < "n" ≤ 5}`

Answer 1

N = {1, 2, 3, 4, …..}

n ∈ {3, 4, 5}

If n = 3, y = `4/(3(3)) = 4/9`

If n = 4, y = `4/(3(4)) = 4/12`

If n = 5, y = `4/(3(5)) = 4/15`

Q = `{4/9, 4/12, 4/15}`

n(Q) = 3