जॉइन Examsbookउत्तर : 4. "1.5 kmph"
A boy can swim in still water at 4.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is ?5
प्र: A boy can swim in still water at 4.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is ?
- 11.8 kmphfalse
- 22 kmphfalse
- 32.2 kmphfalse
- 41.5 kmphtrue
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उत्तर : 4. "1.5 kmph"
व्याख्या :
Answer: D) 1.5 kmph Explanation: Speed of Boy is B = 4.5 kmph Let the speed of the stream is S = x kmph Then speed in Down Stream = 4.5 + x speed in Up Stream = 4.5 - x As the distance is same, => 4.5 + x = (4.5 - x)2 => 4.5 + x = 9 -2x 3x = 4.5 x = 1.5 kmph