<human>:  Dana normally drinks a 500 ml bottle of soda each day. Since the 500 ml bottles are currently out of stock at the store, she buys a 2-liter bottle of soda instead. If Dana continues to drink 500 ml of soda each day, how long will the 2-liter bottle of soda last? There are 1,000 ml in 1 liter.
<bot>: How many ml are in a 2-liter bottle of soda? ** There are 2*1,000 ml = <<2*1000=2000>>2,000 ml in a 2-liter bottle of soda.
How many days will the 2-liter bottle of soda last? ** A 2-liter bottle of soda lasts 2,000/500 = <<2000/500=4>>4 days.
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