Answer:
The mode would not increase or decrease.
Step-by-step explanation:
I say this because the mode is the value(s) in the data set that occur most frequently. 30 is the mode before adding 80 because 30 is in the set 3 times, more than the other values. Because 80 would be the only 80 in the set it would not become the mode once added. I hope this explained my reasoning and helped!
