Three LightHouse Keeper Bridge Crossing Puzzle | MindYourLogic Bridge Crossing Puzzle

Three lighthouse keepers need to cross a bridge at night. The bridge is unstable and will collapse in 10 minutes. They have only one lantern, which must be carried while crossing. Each keeper moves at a different speed:

Keeper X: 1 minute
Keeper Y: 4 minutes
Keeper Z: 5 minutes
To solve this puzzle, all three keepers must cross the bridge before it collapses, minimizing the total crossing time while adhering to the constraints of the lantern and the bridge.

Steps:
Initial Crossing:

Keepers X and Y cross the bridge together with the lantern. This takes 4 minutes (the time of the slower keeper, Keeper Y).

Return Trip:

Keeper X returns with the lantern. This takes an additional 1 minute.
Total time so far: 5 minutes.

Final Crossing:

Keepers X and Z cross the bridge together with the lantern. This takes 5 minutes (the time of the slower keeper, Keeper Z).
Total time so far: 10 minutes.

Conclusion:
By following these steps, all three lighthouse keepers cross the bridge in 10 minutes. The solution ensures that the lantern and the differing speeds of the keepers are managed effectively, allowing all keepers to cross safely before the bridge collapses.