Plz answer I will get a full mark in two pop quizzes if you helped me.

What is the area of triangle abc if a = 8, b = 11, and c = 15?

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 ordered pair (c, d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15