Using a;b instead of p1;p2 :

(28a + 48b)(1 + r) = a

(62a + 22b)(1 + r) = b

Divide 'em:

a / b = (28a + 48b) / (62a + 22b)

a / b = (14a + 24b) / (31a + 11b)

Cross multiply:

31a^2 + 11ba = 14ba + 24b^2

31a^2 - 3ba - 24b^2 = 0

Using quadratic:

a = [b(3 +- sqrt(2985)] / 62 : a = ~.92959925b or ~-.832825b

Ya'll ok with that?