Ineed this answer, but i'm pretty stuck on it.

David bought a poster for an art project. the poster is 2.7 feet wide and 3.9 feet tall. what is the area of the poster?

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?

X+ y = 5 ; x - y =3 solve using linear combination