## College Algebra (10th Edition)

r = $\frac{\frac{A}{P} - 1 }{t}$
A = P(1 + rt) To make "r" the subject, $\frac{A}{P}$ = 1 +rt $\frac{A}{P}$ - 1 = rt r = $\frac{\frac{A}{P} - 1 }{t}$