Question

If A = {1, 2, 3, 4, 5, 6, 7, 8, 9}, determine the truth value of the following statement:

∃ x ∈ A, such that x + 7 ≥ 11.

Answer 1

Clearly x = 1 ∈ A, x  = 2 ∈ A and x = 3 ∈ A satisfies x + 7 ≥ 11. So the given statement is true, hence its truth value is T.