Answer to Yahoo! question

Hey!
       Here's the solution:


Momentum Conservation:

Since the boat is at rest initially, the total momentum is zero. So it has to be zero after the mass is thrown.

Initial Momentum = 0
Final Momentum = (77 + 136) * v + (15 * 4.4) where v is the final velocity of the boat
=> (77 + 136) * v + (15 * 4.4) = 0
=> 213 * v + 66 = 0
=> v = -66 / 213 = -0.3098591549295775
The boat moves in the opposite direction to where the package was thrown with a velocity of -0.3098591549295775.

Good luck!

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