Answer:
For 80 people, Elena would need
14 packs of plates and 10 packs of cups
She would have at least 80 of each.
I am not completely sure of this, sorry if wrong.
Step-by-step explanation:
80 people
8 cups per pack
6 plates per pack
8, 16, 24, 32, 40, 48, 56, 64, 72, 80
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84
LCM (least common multiple) = 24