Answer: The number of cups of flour needed for 9 cups of sugar = 12.
Step-by-step explanation:
Equation of direct proportion between two quantities x and y :
[tex]\dfrac{x_1}{y_1}=\dfrac{x_2}{y_2}[/tex]
Let x= the number of cups of flour needed for 9 cups of sugar.
Put [tex]x_1=4,\ y_1=3,\ y_2=9, x_2=x[/tex]
[tex]\dfrac{4}{3}=\dfrac{x}{9}\\\\\Rightarrow\ x=\dfrac{9\times4}{3}\\\\\Rightarrow\ x=12[/tex]
Hence, the number of cups of flour needed for 9 cups of sugar = 12.
