The total percentage the class needs to get is 18.75 because 25 x .75 = <<25*.75=18.75>>18.75
The total percentage the class has absent the one student is <<18.48=18.48>>18.48
The lowest the absent student can get and still have a pizza party is 27% because (18.75-18.48)x 100 = <<(18.75-18.48)*100=27>>27
#### 27