Finding rafts velocity relative to the water using 2 masses and one velocity

[darktrini123]

Homework Statement

A 50 kg person walks across a 250 kg raft at a constant speed of 2m/s. What is the velocity of the raft relative to the water?

Homework Equations

The Attempt at a Solution

Let m = mass of the person
M = mass of the raft
v = velocity of the person relative to the water
V = velocity of the raft relative to the water
v=V+2 so V=v-2

mv + MV = 0
mv + M(v-2) = 0
mv + Mv - 2M = 0
(m+M)v - 2M = 0
(m+M)v = 2M
v= 2M/(m+M)

v= 2(250)/(50+250)
v= 500/300
v= 1.67 m/s

V= v-2
V= 1.67 - 2
V= -.33 m/s
Ans: -.33 m/s

 

[zorro]

Your answer is right according to me.
Whats the problem?

 

[darktrini123]

I just wanted to make sure the answer was correct