10 less than a number K equals five

What’s the equation???

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?

Name each raycalculation tip: in ray "ab", a is the endpoint of the ray.

Determine the area of a triangle with (see picture below)