Math, asked by sahilrajput3304, 1 year ago

A man can row 10.2 km downstream in 18 minutes. If the speed of the stream is 3.5 kmph, how much time he would take to cover 121.5 km upstream? (in hours)

Answers

Answered by thyphamxuan
1

Downstream:

v(boat/ bank)= v(boat/ stream)+v( stream/bank) = s/t

<=> v( boat/stream) +3.5= 10.2/(18/60) => v(boat/stream)=30.5kmph

Upstream:

v(boat/bank) = v( boat/stream) - v( stream/bank) =30.5 - 3.5 =27 kmph

t' = s' / v(boat/bank) = 121.5/27 =4.5 hrs

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