Let's find the required ratios first: to get to the relative percentages, we'll simply have to multiply by 100.
Since there are 16 girls, 10 boys and 9 adults, there are
[tex] 16+10+9 = 35 [/tex]
people in total.
So, the ratio of girls is
[tex] \dfrac{16}{35} \approx 0.4571 = 45.71\% [/tex]
The ratio of boys is
[tex] \dfrac{10}{35} \approx 0.2857 = 28.57\% [/tex]
The ratio of adults is
[tex] \dfrac{9}{35} \approx 0.2571 = 25.71\% [/tex]