Simplify the ratio by dividing both numbers by their HCF.<br><br>
&bull; Oil : Flour = \(10 : 450\)<br>
&bull; HCF of 10 and 450 is 10.<br>
&bull; \(10 \div 10 = 1\), \(450 \div 10 = 45\)<br>
&bull; Ratio = \(1 : 45\)<br><br>
Final Answer: 1 : 45