Final answer:
Each fruit cup contained 1/15 of the original melon after Mrs. Sims cut the melon into fifths and distributed four pieces to her children.
Step-by-step explanation:
Mrs. Sims cut a melon into fifths. She then gave one piece to each of her four children, leaving one fifth of the melon. This leftover piece was used to make three equal fruit cups. To determine what fraction of the original melon she used for each fruit cup, we can divide the remaining melon (1/5) by the number of fruit cups (3).
Dividing 1/5 by 3 gives us 1/15. Therefore, each fruit cup contained 1/15 of the original melon.