A boat can row 36 km downstream in the same time as it takes to row 24 km upstream. If the speed of the stream is 3 km/h, what is the speed of the boat in still water?
A boat can row 36 km downstream in the same time as it takes to row 24 km upstream. If the speed of the stream is 3 km/h, what is the speed of the boat in still water?
एक नाव धारा की दिशा में 36 किमी जा सकती है उतने ही समय में वह धारा की विपरीत दिशा में 24 किमी जा सकती है। यदि धारा की चाल 3 किमी/घंटा है, तो स्थिर जल में नाव की चाल ज्ञात कीजिए।
Detailed Solution & Logic
Correct Answer:
15 km/h
Step 1: Let speed of boat in still water = x km/h
Downstream speed = $(x+3)$ km/h
Upstream speed = $(x-3)$ km/h
Given time is same:
$\frac{36}{x+3}=\frac{24}{x-3}$
Step 2: Cross multiply
$36(x-3)=24(x+3)$
$36x-108=24x+72$
$12x=180$
$x=15$
Final Answer: 15 km/h
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