Answer:
90 Couples
Explanation:
There were 250 total people at the beginning at the party. 70 people left at 11pm.
Subtract 70 from 250:
![250-70=180](https://img.qammunity.org/2021/formulas/mathematics/middle-school/giwz064e5h8bjubsjcghocsi5vxjn5jrdj.png)
There were 180 people that stayed.
A couple consists of two people. The question asks how many couples stayed at the party, not people.
Divide 180 by 2:
![(180)/(2)= 90](https://img.qammunity.org/2021/formulas/mathematics/middle-school/1m9ps48wbq2icaago3asaqq9zyelwb2o1b.png)
There would be 90 couples that stayed at the party.