Given:
A) 6:9
[tex]6\colon9=\frac{6}{9}=\frac{3\cdot2}{3\cdot3}=\frac{2}{3}=2\colon3[/tex]It shows that the simplest form of 6:9 is 2:3.
B) 10:24
[tex]\frac{10}{24}=\frac{5\cdot2}{2\cdot12}=\frac{5}{12}=5\colon12[/tex]It shows that the simplest form of 10:24 is 5:12.
C) 4:36
[tex]4\colon36=\frac{4}{36}=\frac{1\cdot4}{4\cdot9}=\frac{1}{9}=1\colon9[/tex]It shows that the simplest form of 4:36 is 1:9.
D) 8:15
[tex]8\colon15=\frac{8}{15}[/tex]It implies that the ratio of 8:15 is in the simplest form.
Answer: D) 8:15