Answer: 43:100
Explanation:
Percentage of bicycles that are blue = 32%
Percentage of bicycles that are red = 25%
Percentage of bicycles that are green = 25%
Percentage of bicycles that are black = 18%
Percentage of bicycles that are red or black = 25% + 18% = 43%
Therefore, 43% will be written in ratio form as 43:100