A boat's still water speed is 2 km/hr, and its upstream speed is 1 km/hr. What is the current's speed________?
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Answer: C. 1km/hr
Explanation
Upstream boat speed is calculated by subtracting the speed of the water current from the still water speed. Substituting the given values into the formula gives one equals two minus the unknown current speed value. Solving this straightforward linear equation reveals that the current speed is exactly one kilometer per hour. Boat movement against a flowing water current experiences resistance that reduces its effective ground travel speed. Still water speed represents the inherent propulsion velocity of the vessel in completely calm and stationary conditions. Relational speed equations in navigation combine vessel propulsion and water current velocity vectors algebraically.
One point five kilometers per hour miscalculates the algebraic difference between the still water and upstream speeds. Three kilometers per hour incorrectly adds the current speed instead of subtracting it for upstream travel conditions. None of these is incorrect because the third option provides the accurate mathematical solution to the problem.
- Subject
- Mathematics
- Category
- Mathematics
- Topic
- —
- Difficulty
- medium
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