Answer:
The answer is 64 people.
Explanation:
If they invite 64 people and all of them show up you multiply that by 30 you get 1,920 add 70 to that and you get 1,990. The reason that 64 is the maximum is because if it were 65 it would go over their budget and if it were below 64 then we wouldn't be getting the greatest number possible.