Paula wants to go on the go-kart 1 time and the bumper cars 4 times.
The number of tickets needed for the go-karts is 1 × 4 = <<1*4=4>>4.
The number of tickets needed for the bumper cars is 4 × 5 = <<4*5=20>>20.
Paula needs 4 + 20 = <<4+20=24>>24 tickets.
#### 24