Given the following frequency table, find the modal class: \n\nClasses: 10-20, 20-30, 30-40, 40-50, 50-60 \nFrequencies: 5, 7, 12, 9, 6

Step 1 ：Step 1: Identify the class with the highest frequency. In this case, the class with the highest frequency is 30-40 with a frequency of 12.

Step 2 ：Step 2: Therefore, the modal class of the frequency table is 30-40.