1. Traveling downstream, a boat can go 18 km in 2 hrs. Going upstream, it makes only 2/3 this distance in twice the time. What is the rate of the boat in still water, and what is the rate of the current??
2. A river streamer travels 48 km downstream in the same time that it travels 32 km upstream. The streamer's engines drive in still water at a rate which is 16 kph greater than the rate of the current. Find the rate of the current.
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2007-11-17 19:02:18 · 0 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
1. 18/(b + c) = 2 and 12/(b -- c) = 4
=> b + c = 9 and b -- c = 3
adding, 2b = 12 => b = 6
and c = 9 -- b = 9 -- 6 = 3
rate of boat = 6 km/h
rate of current = 3 km/h
2. s = (c + 16) km/h
also 48/(s + c) = 32/(s -- c)
=> 3(s -- c) = 2(s + c)
=> s = 5c
=> 5c = c + 16 => 4c = 16 => c = 4
and s = c + 16 = 4 + 16 = 20
steamer @ 20km/h and current @ 4km/h
2007-11-17 19:24:36 · answer #1 · answered by sv 7 · 0⤊ 0⤋
Rate Of Current
2016-10-18 08:01:48 · answer #2 · answered by lograsso 4 · 0⤊ 0⤋
A motor boat travels 11 mph in still water. It takes 3 hours longer to travel 65 miles upstream than it does going downstream. Find the rate of the current. (Hint: Use 11+x as the rate going downstream and 11-x as the rate going upstream. Round answer to the nearest tenth.) rt=d up (11-x)(t+3)=65 down (11+x)t=65
2016-03-19 02:29:10 · answer #3 · answered by ? 4 · 0⤊ 0⤋
1.
Vb + Vs = 18 km/2 hr
Vb - Vs = (2/3)(18 km)/4 hr
2Vb = 9 + 3 = 12 kph
Vb = 6 kph
Vs = 3 kph
2.
(Vb + Vs)t = 48
(Vb - Vs)t = 32
Vb = Vs + 16
(2Vs + 16)/48 = 16/32
2Vs + 16 = 24
2Vs = 8
Vs = 4 kph
2007-11-17 19:41:25 · answer #4 · answered by Helmut 7 · 1⤊ 0⤋