Div. of 8% * $50 for 3 more years (shares are retractable at par) plus the par value in 3 years, discounted at the required rate of return.
Since divs are constant it is not a perpetuity, no need for the growth rate.
Greetings, here is how you get 45.02 on your financial calculator:
FV = 50
PMT = 1
I = 3
N = 12
[Compute] PV = 45.02
FV = par retractable value = 50
PMT = quarterly dividend = (50*0.08)/4 = 1
I = 12% required return divided by 4 to make it quarterly = 3
N = 12 quarters
This gives you PV = $45.02 … without over complicating things, just think of intrinsic value of preferred stock as the present values of its cash flows. Here the cash flows are the 1 dollar quarterly dividends plus the 50 dollar payment when the retraction happens in 3 years. The discount rate is the required rate of return for such stock. They gave it all to you here but threw in some extra stuff to try to distract you.