As she gave 1 balloon out, 12 balloons floated away plus she gave away 9 more balloons so she is down 1+12+9 = <<1+12+9=22>>22 balloons
She started with 50 and gave/lost 22 balloons so she has 50-22 = <<50-22=28>>28 balloons
She also took her coworkers last 11 balloons so her new total is 28+11 = <<28+11=39>>39 balloons
#### 39