Bono and Edge Cross: 2 minutes
Bono returns: 1 minute (Sum = 3 minutes)
Larry and Adam Cross: 10 minutes (Sum = 13 minutes)
Edge returns: 2 minutes (Sum = 15 minutes)
Bono and Edge Cross: 2 minutes (Sum = 17 minutes)
A second solution is:
Bono and Edge Cross: 2 minutes
Edge returns: 2 minutes (Sum = 4 minutes)
Larry and Adam Cross: 10 minutes (Sum = 14 minutes)
Bono returns: 1 minute (Sum = 15 minutes)
Bono and Edge Cross: 2 minutes (Sum = 17 minutes)