First find how many liters of the seawater are salt: 2 liters * 20% = <<2*20*.01=.4>>.4 liters

Then multiply that amount by 1000 ml/liter to find the number of ml of salt Jack gets: .4 liters * 1000 ml/liter = <<.4*1000=400>>400 ml

# Answer

400
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Jack is stranded on a desert island. He wants some salt to season his fish. He collects 2 liters of seawater in an old bucket. If the water is 20% salt, how many ml of salt will Jack get when all the water evaporates?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
400
Jack is stranded on a desert island. He wants some salt to season his fish. He collects 2 liters of seawater in an old bucket. If the water is 20% salt, how many ml of salt will Jack get when all the water evaporates?
train