pls help me figure this out

Answer:
C. [tex]\frac{27}{225}=\frac{b}{100}[/tex]
Step-by-step explanation:
To find the number of black ribbons one would have subtract the amount of red ribbons from the total number of ribbons. Then one would have to express it as a proportion. Part over whole equals percent over 100. The number of black ribbons over total ribbons equals "b" over 100.