I need some help with this !!

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?

Find the greatest common factor of -30x 4 yz 3 and 75x 4 z 2.

Can some one me with these questions