What is the percent increase when 7,200 increases by 1,800? help asap

Abby is preparing fruit punch for her party. she starts with a bowl filled with liquid that has 1/2 fruit juice and 1/2 sprite, but she decides it's too fruity. so she pours out 1/4 of the liquid, and then fills the bowl up again with sprite. what fraction of the punch is now sprite?

Which of the choices shown could be used to prove that aacp=abcp ?

Combine like terms to make a simpler expression 3z+z