In 1973 a group of political activists escaped one of the most secure prisons in USA and planned to move to Canada. They soon reached the bank of Detroit River that separates USA from Canada. The sun set as Marcus, Vincent, and Leo arrived at the riverbank with Sarah, Emma, and Maya—their girlfriends. The group had just finished a long journey, and freedom waited across the Detroit River. Each girl wore a diamond necklace worth 1 million dollars, that each couple planned to sell after reaching Canada and starting new lives. A risky river and a single rickety boat stood between them and safety.
Marcus checked how many people the boat could carry. “It fits two people max. More than that and it’ll sink.”
Vincent’s eyes gleamed . “Listen up—if any of you girls end up alone with me or Leo while your boyfriend’s away, well… our work doesn’t always care about being loyal. Those diamond necklaces of yours make you hard to resist. Don’t act surprised if you girls get snatched.”
Leo nodded. “Same goes for me. We’re outlaws now, not good guys.”
The girlfriends exchanged worried looks. Sarah clutched Marcus’s arm. “So how do we all get across without someone being… kidnapped?”
The issue was clear: a woman couldn’t be near a man who wasn’t her partner anywhere around the river or on the boat. With one boat that holds two people, the journey across would require smart thinking.
Your Task: You must figure out how to use a boat that fits at most 2 people to move this group of fugitives over the river. You need to make sure no girl is away from her partner at any time when she’s close to another guy.
——– View the answer ——–
The Solution:
- Two women cross (Sarah and Emma)
- One woman returns (Sarah returns. Emma stays)
- Two women cross (Sarah and Maya cross)
- One woman returns (Emma returns. Sarah and Maya stay)
- Two men cross (Marcus and Leo cross)
- One man and one woman return (Marcus and Sarah return. Maya and Leo stay)
- Two men cross (Marcus and Vincent cross)
- One woman returns (Maya returns. Marcus, Vincent and Leo stay)
- Two women cross (Sarah and Emma cross)
- One woman returns (Emma returns. Sarah, Marcus, Vincent and Leo stay)
- Two women cross (Maya and Emma cross- final)
