A farmer often makes a trip with a squirrel, acorns, and a fox. During each trip he must cross a river in a boat in which he can't take more than one of them with him each time he crosses. Since he often has to leave two of them together on one side of the river or the other, how can he plan the crossings so that nothing gets eaten, and they all get across the river safely?

Short Answer

Expert verified
Answer: The correct order of steps is as follows: 1. Take the squirrel across the river. 2. Return alone. 3. Take the fox across the river. 4. Return with the squirrel. 5. Take the acorns across the river. 6. Return alone. 7. Take the squirrel across the river for the last time.

Step by step solution

01

Identify the dangerous combinations

The Farmer should know that the only dangerous combination is leaving the squirrel and acorns alone together. The squirrel will eat the acorns if they are left unattended. The fox won't eat the squirrel, so it is safe to leave them alone together.
02

First crossing

The Farmer should take the squirrel across the river first. This leaves the acorns and fox safe on the first side of the river.
03

Return trip

The Farmer should return to the first side of the river alone. This leaves the squirrel safe on the second side of the river.
04

Second crossing

The Farmer should now take the fox across the river. This leaves the acorns alone and safe on the first side of the river.
05

Second return trip

The Farmer should return to the first side of the river with the squirrel, since leaving the squirrel with the acorns will be a dangerous combination.
06

Third crossing

The Farmer should take the acorns across the river. This leaves the squirrel and fox together and safe on the first side of the river.
07

Final return trip

The Farmer should return to the first side of the river alone. This leaves the squirrel and fox safe on the first side of the river, while the acorns are safe on the second side.
08

Final crossing

The Farmer should take the squirrel across the river for the last time. This successfully transports all of them to the second side of the river without any dangerous combinations. Following these steps, the farmer can safely transport the squirrel, acorns, and fox across the river without leaving any of them in danger of being eaten.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Critical Thinking
Critical thinking is a fundamental skill, particularly in problem-solving disciplines such as engineering. In the case of our farmer who needs to safely transport his squirrel, acorns, and fox across the river, he must engage in strategic planning to avoid any unfortunate outcomes.

Critical thinking involves assessing the situation comprehensively, which includes identifying potential risks—namely, the possibility of the squirrel eating the acorns. The farmer must then apply logic to devise a plan that mitigates these risks. By breaking down the process into manageable steps, logical analysis leads to a sequence of actions that ensure safety for all parties involved.

Students can enhance their critical thinking abilities by practicing exercises like these, which require analysis of constraints and sequential logic. A key aspect of critical thinking showcased here is foreseeing the consequences of actions taken, a skill invaluable in all fields of study and professional life.
Engineering Principles
Engineering is about applying principles of science and mathematics to develop solutions to problems. In the textbook exercise, although not involving conventional engineering, the farmer applies engineering thinking to overcome a logistical challenge.

The principles of engineering can be distilled into stages: define the problem, brainstorm solutions, plan the procedure, and execute while monitoring for unexpected issues. In this scenario, the problem is defined by the risk factors—acorns cannot be left with the squirrel, but there's no risk between the squirrel and the fox. Brainstorming and planning result in a step-by-step solution that systematically prevents danger.

This exercise promotes comprehending the problem, delineating constraints, and sequentially testing solutions—all of which are critical not just in engineering but also in everyday life decision-making processes. These principles lay the foundation for future engineers to approach complex real-world problems with confidence and structured methodology.
Logic Puzzles
Logic puzzles are an entertaining and effective method to sharpen one's cognitive abilities, particularly in pattern recognition, problem-solving, and strategic thought. The river-crossing problem is a classic example of a logic puzzle where the key lies in understanding the rules and the relationships between different elements.

In this puzzle, the farmer acts within a set of constraints and must determine a sequence that doesn't lead to any negative outcomes. It's akin to a game of chess where each move has implications for subsequent moves. Logic puzzles like these teach learners to anticipate the outcomes of various sequences of actions, which is a vital skill in academic disciplines and real-world scenarios alike.

Engaging with logic puzzles can be an excellent way to fine-tune one's logical reasoning and deduction skills. They encourage looking at a problem from multiple angles to find a solution, which is a valuable expertise in fields that rely on data analysis, troubleshooting, and strategic planning.

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