Well, there is actually a formula for this kind of exercises:
n is the price the land had in the third year year
2500=n-nx0.6
2500=n(1-0.6)
2500=nx0.4
n=2500:0.4
n=6250
m is the price the land had in the second year
6250=m-mx0.6
6250=m(1-0.6)
6250=nx0.4
p=6250:0.4
p=15625
p is the price the land had in the first year
15625=p-px0.6
15625=p(1-0.6)
15625=px0.4
p=15625:0.4
p=39,062.5 <- this should be your answer. Hope this helps.
