A boat travels at 60 kmph in still water with a 20 kmph current. Find its downstream and upstream speeds.
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Answer: B. 80, 40 kmph
Explanation
Downstream speed is calculated by adding the still water speed and the current speed together. Adding sixty kilometers per hour and twenty kilometers per hour yields an exact downstream speed of eighty. Upstream speed is found by subtracting the current speed from the still water speed to get forty. Boat speed in still water represents its velocity independent of external water currents. Current speed acts as a vector that either assists or hinders the motion of the watercraft. Downstream travel benefits from current assistance while upstream travel fights against the water flow.
Navigational planning for river transport requires calculating travel times using current velocity vectors. Rowing athletes adjust their pacing strategies based on whether they are moving with or against the tide. Hydrological engineering studies watercraft performance under varying river discharge conditions. Option a underestimates both speeds by subtracting or miscalculating the current vector values. Option c swaps the upstream and downstream speeds incorrectly relative to the direction of flow. Option d implies incorrect arithmetic addition and subtraction of the velocity components.
- Subject
- Mathematics
- Category
- Mathematics
- Topic
- —
- Difficulty
- medium
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