400 should be the answer. Hope this helps!
14. B (4, -2)
15. I am not exactly sure about this one but I would say either A or B.
Compound interest formula = a=P(1+r/n)^nt
P= lump sum to deposit (solving for)
A= amount accumulated over the entire time (20000)
n= number of times interest is compounded annually (1)
r= rate of interest (0.82)
T= total number of years (15)
20000=P(1+0.082/1)^1*15
20000=P(1.082)^15
20000=P(3.26143638)
20000/3.26143638=P
P=$6132.2674