He needs 10*6=<<10*6=60>>60 feet

He loses 20*.25=<<20*.25=5>>5 feet each time

So he gets 20-5=<<20-5=15>>15 feet from each piece

That means he needs 60/15=<<60/15=4>>4 pieces of rope

# Answer

4
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Tom needs to lower a rope down 6 stories.   One story is 10 feet.  The only rope being sold is 20 feet long but you lose 25% when lashing them together.  How many pieces of rope will he need to buy?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
4
Tom needs to lower a rope down 6 stories.   One story is 10 feet.  The only rope being sold is 20 feet long but you lose 25% when lashing them together.  How many pieces of rope will he need to buy?
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