- A12
- B2
- C24
- D10
Step-by-Step Solution
Downstream speed = 42/3 = 14 km/h; upstream speed = 30/3 = 10 km/h. Still-water speed = (14 + 10)/2 = 12 km/h.
Answer: A) 12
A motor launch covers 42 km downstream in 3 hours and 30 km upstream in 3 hours. What is its speed in still water in km/h?
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