a) You have:
[tex]f(0) = 270000\\
f(1) = 1.04f(0), \\
f(2) = 1.04f(1) = 1.04(1.04f(0)), \\
f(t) = 1.04f(t-1) = 1.04(1.04f(t-2)) ... = 1.04^{t}f(0) = 1.04^{t}*270000 [/tex]
b) [tex]f(2004-1998) = 1.04^{2004-1998} * 270000 = 341636[/tex]
c)
[tex]1.04^{x-1998} * 270000 \geq 534094
\\
x - 1998 \geq {ln( \frac{534094}{270000} )}/{ln(1.04)}
x \geq 2015.4
x = 2016[/tex]
