Pls answer and explain

My favorite songstress gives away 25% of this side of her signature fragrance collection to her charity last month her sales were 1200 how much of her sales did she donate

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

What does x = in this equation x+3+2x=x+5