Part A:
Yes, the numbers of white and yellow flowers in Cara's arrangements are proportional.
yellow flowers = y
white flowers = w
5y = 3w
Therefore, the numbers of white and yellow flowers in Cara's arrangements are proportional.
Part B:
yellow flowers = y
white flowers = w
6y = 4w
Therefore, the numbers of white and yellow flowers in Hector's arrangements are proportional.