The question is:
A man can row at 5km/h in still water. He rows upstream from a bridge towards his house. The water is flowing at 2km/h and it takes 4 hours to get from the bridge to his house. How far is it from the bridge to his house?
2007-06-14 06:01:39 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
He would go 20 km (4h * 5 km/h), but the water would flow 8 km (4h * 2 km/h)in the opposite direction giving a net distance of 12 km.
2007-06-14 06:06:59 · answer #1 · answered by El Gigante 4 · 0⤊ 0⤋
If the water is flowing at 2 km and he can row at 5 km there is a net gain of 3 km per hour. At four hours his house would be 12 km distant.
But it would have been far more interesting had you presented both of the answers that you and your friend came up with.
2007-06-14 13:06:01 · answer #2 · answered by old lady 7 · 0⤊ 0⤋
Only 12 km
2007-06-14 13:11:24 · answer #3 · answered by nnmaurya 2 · 0⤊ 0⤋
it has already been calculated but in words:
If he would not row at all he would go downstreams at 2km/h. So to stand still (compared to the river bank) he has to row at 2km/h. Any rowing speed above 2 km/h will bring him forward compared to the river bank. In case of 5 km/h he will make 3 km/h compared to the river bank
2007-06-14 13:16:19 · answer #4 · answered by Martin S 7 · 0⤊ 0⤋
12 Kilometers
2007-06-14 13:06:37 · answer #5 · answered by Lan 3 · 0⤊ 0⤋
Based on mentioned conditions, mathematically;
(5km/hr - 2 km/hr) x 4 hr = 12km
2007-06-14 13:08:39 · answer #6 · answered by ebenu2 1 · 0⤊ 0⤋
wouldnt it be 5-2=3x4=12
assumeing he has keept the same pase of 5km/hr
2007-06-14 13:08:10 · answer #7 · answered by more then you know 2 · 0⤊ 0⤋
12 km.
Doug
2007-06-14 13:04:52 · answer #8 · answered by doug_donaghue 7 · 0⤊ 0⤋