Traveling 20 hours due east at 30 kilometers per hour, the ship sailed 20*30=<<20*30=600>>600 kilometers the first day.

If half the distance to the destination is 600 kilometers, then 2*600=<<2*600=1200>>1200 kilometers is the total distance from start to destination.

One-third of the distance from start to destination is 1/3 * 1200 = <<1200/3=400>>400 kilometers.

Thus, the wind storm blew the ship in a westward direction for 600 - 400 = <<600-400=200>>200 kilometers.

# Answer

200
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On the first day of the journey, the Skipper sailed his ship halfway to the destination by traveling due east for 20 hours at a speed of 30 kilometers per hour, and then turned the ship's engines off to let them cool down. But while the engines were off, a wind storm blew his vessel backward in a westward direction.  After the storm, the Skipper used his GPS device to determine the new location of the ship, and he discovered that he was only one-third of the way to his destination.  How many kilometers had the ship been blown in a westward direction by the storm?
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200
On the first day of the journey, the Skipper sailed his ship halfway to the destination by traveling due east for 20 hours at a speed of 30 kilometers per hour, and then turned the ship's engines off to let them cool down. But while the engines were off, a wind storm blew his vessel backward in a westward direction.  After the storm, the Skipper used his GPS device to determine the new location of the ship, and he discovered that he was only one-third of the way to his destination.  How many kilometers had the ship been blown in a westward direction by the storm?
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