Answer:
Price of roses is proportional to the number of roses.
Step-by-step explanation:
Let the price of roses are proportional to the number of roses.
Equation representing this phenomenon will be,
P = k(R) ⇒ k = 
where 'P' = price of the roses
R = Number of roses
k = Proportionality constant
If we substitute the values of P and R and we get the same value of constant 'k', then the equation will be true.
For R = 3 and P = $9
k = 
k = 3
For R = 6 and R = 18
k = 
k = 3
K is same in both the conditions, therefore, Price of roses are proportional to the number of roses.