Question

A = 1 + prt; for r

Answer 1

Plug in your numbers.

Answer 2

No, quinnisaghost, the original problem is A = 1 + prt
Your right side is wrong.
Subtract 1 from both sides instead of p
You get (A - 1)/pt = r

Answer 3

Subtract the 1 over to the other side
A−1=prt

Now divide the p and t to the other side
(A−1)/(pt)=r

Answer 4

Is that right?

Answer 5

Looks good to me.

Answer 6

Yay.