Question 874f12bd

Advanced Math - Nonlinear equations in one variable and systems of equations in two variables

$\frac{20}{p} = \frac{20}{q} - \frac{20}{r} - \frac{20}{s}$

The given equation relates the positive variables $p$ , $q$ , $r$ , and $s$ . Which of the following is equivalent to $q$ ?