If she invited 20 friends, then the number of friends who came with one more person is 1/2*20 = <<20*1/2=10>>10.
If the 10 friends came with 10 more people, the total number of guests becomes 20+10 = 30 guests.
If you add Ashley, the total number of people in the party is 30+1 = <<30+1=31>>31 people
#### 31