Answer:
The required expression would be [tex]4(4)^{t-1}[/tex]
Step-by-step explanation:
Since, the amount formula is,
[tex]A=P(1+r)^t[/tex]
Where,
P = invested amount,
t = number of periods,
r = rate per period,
Given,
The invested amount at month 1, P = 4,
Number of periods from month 1 to month 4, t = 3
Amount at the end of fourth month, A = 256.
By substituting the values,
[tex]256=4(1+r)^3[/tex]
[tex]64=(1+r)^3[/tex]
[tex]4=1+r[/tex]
[tex]r = 4-1=3[/tex]
Hence, the amount of money at the end of t months.
[tex]A=4(4)^{t-1}[/tex]