Real World Applications of the (x-y)/(x+y) Equation

[mathisp64]

Homework Statement

Real world use of (x-y)/(x+y).

Homework Equations

(x-y)/x

The Attempt at a Solution

(x-y)/x solves for the mean difference ratio. I had 400 oranges and sold 100. 400-100/400 gives .75 or 75% remaining. I do not understand where I would use the difference over sum equation. The answer: .6 or 60% using this equation baffles me.

Can anyone set me straight on this.

Thanks!

 

[tiny-tim]

welcome to pf!

hi mathisp64! welcome to pf!

(x-y)/x solves for the mean difference ratio. I had 400 oranges and sold 100. 400-100/400 gives .75 or 75% remaining. I do not understand where I would use the difference over sum equation. The answer: .6 or 60% using this equation baffles me.

you have a party with 70 girls and 62 boys …

(x-y)/(x+y) tells you how unbalanced it is ​

 

[mathisp64]

Thanks, that was exactly what I was needing to know.