Final answer:
The union of the sets G and H is {p, q, r, s, m, n, t}.
Step-by-step explanation:
The union of two sets G and H is the set that contains all the elements from both sets. In this case, G = {p, q, r, s} and H = {m, n, t}. Therefore, the union of G and H is {p, q, r, s, m, n, t}.