To find the percentage of girls in class A, we need to divide the number of girls by the total number of students and then multiply by 100. This gives us:
14 / 20 * 100 = 70%
To find the percentage of girls in class B, we need to divide the number of girls by the total number of students and then multiply by 100. This gives us:
15 / 25 * 100 = 60%
Thus, the percentage of girls in class A is 70%, and the percentage of girls in class B is 60%.