# It takes a boat 2 hrs to travel 16 miles down stream. The same boat takes 4 hrs for the return trip.?

Whats the speed of the water?

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• Julian
Lv 6
8 years ago

v = speed of the boat

c = speed ot the water (current)

(v+c)*2 = 16 => v+c = 8

(v-c)*4 = 16 => v-c = 4

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2c = 8-4 = 4

c = 2

answer : speed of the water = 2mph

• Anonymous
8 years ago

The speed of the boat + the river is its speed downstream, so

speed = distance/time

= 16/2

= 8 m/hr

The speed of the boat - the river is its speed upstream, as the water is travelling the opposite direction to the boat, so

speed = 16/4

= 4 m/hr

let the speed of the boat = b, and the speed of the water = w

b + w = 8

b - w = 4

add the two equations together to get

2b = 12

b = 6

Substitute into one of the above equations

6 + w = 8

w = 2 miles/hour

• 8 years ago

S=vxt so v=s/t.

S= 16 miles

t= 4 hrs

v= ?

v= 16/4 = 4 miles per hour.

That should be the correct answer.

v = speed

S= distance travelled

t= time

Whoops, used the Dutch formula, I believe the English formula is D=Rxt or something like that.

So S= D, v=R and t stays t. Sorry!

Source(s): Physics
• 4 years ago

formula of velocity: v=d/t, the place V is velocity, D is distance and T is time. appearing some rearranging we get that t=d/v In equation under v is velocity of the boat and r is the fee of the flow 40 8/(v+r)=3 40 8/(v-r)=12 fixing that equation we get that r=6