For this case we first define variables:
x = daisies flowers
y = roses flowers
We write the system of equations:
x + 2y = 33
x = y + 3
Solving the system we have:
x = 13
y = 10
Therefore, the cost of roses is:
2 * y = 2 * 10 = 20 $
Answer:
Roses = $ 20