You are throwing a party, and you need 5 5 liters of yoda soda for every 1 2 12 guests. if you have 3 6 36 guests, how many liters of yoda soda do you need

Set up the proportion, you get 5/12=x/36. Solving for x, you get x=15.

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value