<human>:  Elise is buying more dog food. She buys a 15kg bag then another 10kg bag, and she now has 40kg of dog food. How many kilograms of dog food did Elise already have?
<bot>: How many kilograms of dog food did Elise buy? ** Elise has bought a total of 15 kg + 10 kg = <<15+10=25>>25kg of dog food.
How many kilograms of dog food did Elise already have? ** This means she already had 40 kg – 25 kg = <<40-25=15>>15kg of dog food.
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