So first William and Alan went first which took 2 minutes. Than William goes back and passes back the flashlight to Stacy and Jaime which took 1 minutes. Than Stacy and Jaime cross which took 10 minutes. Than they pass the flashlight to Alan and Alan went across the bridge to pick up William and that took 4 minutes to let Alan pick up William and both of them came back which took a total of 4 minutes. So add those up you get 17 minutes which means that they are on time LET THE CONCERT BEGIN!!!!