Convert both quantities to the same unit, then simplify the ratio.<br><br>
&bull; 2 hours = 2 × 60 = 120 minutes<br>
&bull; Ratio 2 hours : 30 minutes = 120 : 30<br>
&bull; Simplify: divide both by their HCF, 30.<br>
&bull; 120 ÷ 30 = 4, 30 ÷ 30 = 1<br>
&bull; Ratio = 4 : 1<br><br>
Final Answer: 4:1