Number of girls in the band = 12
Total number of students in the band = 17 + 12 = 29
Ratio of number of girls to total students = 12/29
To simplify the ratio, we can divide both the numerator and the denominator by 1:
12/29 = (12 ÷ 1) / (29 ÷ 1)
= 12/29
Therefore, the ratio of the number of girls in the band to the total number of students in the band is 12:29.