I believe you are solving for Interest.
The equation in which you use is: I = P(r)(t), in which:
I = Interest
P = Principle (54000)
r = Interest rate (3%) = (0.03)
t = Time (4 years)
Set the equation:
I = (54000)(0.03)(4)
Simplify:
I = 6480
The amount of interest earn is $6480, bringing the total amount to $60480
~
