Answer:
A. f: the number of friends attending Alisa's party.
Step-by-step explanation:
We know that it takes Alisa 10 minutes to full a dozen balloons, and if each of her friends gets one dozen balloons, and if [tex]f[/tex] is the number of friends, then the total dozens of balloons will be [tex]f[/tex] (because each friend gets a dozen balloons.)
Thus we must know [tex]f[/tex]: the number of friends attending Alisa's party, if we are calculate the time Alisa will take to fill all the balloons.
