Express all quantities in the same unit, then simplify.<br><br>
&bull; 2&nbsp;kg : 2.5&nbsp;kg : 4&nbsp;kg<br>
&bull; Multiply by 10 to clear the decimal: 20 : 25 : 40<br>
&bull; Divide each by 5: 4 : 5 : 8<br>
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Final Answer: 4 : 5 : 8