When Brooke gets twelve more balloons, his total becomes 12+8 = <<12+8=20>>20
When Tracy adds 24 more balloons to her 6, her total number of balloons becomes 24+6 = <<24+6=30>>30
When half of Tracy's balloons pop, she remains with 1/2*30 =<<1/2*30=15>>15
The combined total balloons for the two is 15+20 = <<15+20=35>>35 balloons
#### 35