eighteen over one hundred, or nine over fifty
The fraction is fifty-five over one hundred, which reduced is eleven over twenty.
The result of the spin will be red one half, or fifty percent, of the time. The other one half, or fifty percent, black will come up. In other words there is a fifty percent chance it will be red and a fifty percent chance that it will not. Hence fifty-fifty. With an actual roulette wheel, you have less than a fifty-fifty chance of spinning red.
Fifty percent is one of two
7 over 50 equals 14%.
3/50 = 6%
One hundred fifty percent.