# How do you solve A = P + Prt for r?

Jun 19, 2016

$r = \frac{A - P}{P t}$

#### Explanation:

Solve for r, means make r the subject of the formula, write r in terms of all the other variables.

$P + \textcolor{b l u e}{P r t} = A$

$\text{ "color(blue)(Prt) = A - P " isolate the term which contains } r$

$\text{ } P \textcolor{red}{r} t = A - P$

$\text{ "color(red)(r) = (A - P)/(Pt) " to isolate } r$ divide by $P \mathmr{and} t$