Simplify the ratio by dividing both terms by their highest common factor.<br><br>
&bull; 15 : 5<br>
&bull; HCF of 15 and 5 is 5<br>
&bull; 15 ÷ 5 = 3, 5 ÷ 5 = 1<br>
&bull; Simplified ratio = 3 : 1<br>
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Final Answer: 3 : 1