On Tuesday, Billy ate 2 * 2 = <<2*2=4>>4 apples.

On Friday, he ate 2 * 0.5 = <<2*0.5=1>>1 apple.

On Thursday, he ate 4 * 1 = <<4*1=4>>4 apples.

So for Monday, Tuesday, Thursday, and Friday, Billy ate a total of 2 + 4 + 4 + 1 = <<2+4+4+1=11>>11 apples.

This means that on Wednesday, he must have eaten 20 – 11 = <<20-11=9>>9 apples.

# Answer

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<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Billy ate 20 apples this week. On Monday, he ate 2 apples. On Tuesday, he ate twice as many as he ate the day before. He’s not sure what he ate on Wednesday. On Thursday, he ate four times as many as he ate on Friday. On Friday, he ate half of the amount he ate on Monday.  How many apples did he eat on Wednesday?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
9
Billy ate 20 apples this week. On Monday, he ate 2 apples. On Tuesday, he ate twice as many as he ate the day before. He’s not sure what he ate on Wednesday. On Thursday, he ate four times as many as he ate on Friday. On Friday, he ate half of the amount he ate on Monday.  How many apples did he eat on Wednesday?
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