Betsy jumps half as long as Cindy, who jumps for 12 minutes so Betsy jumps 12/2 = <<12/2=6>>6 minutes
Tina jumps three times as long as Betsy, who jumps for 6 minutes so Tina jumps 3*6 = <<3*6=18>>18 minutes
Tina can jump for 18 minutes and Cindy and jump for 12 minutes so Tina can jump 18-12 = <<18-12=6>>6 minutes longer
#### 6