Answer:
It will take 146 days to earn an interest of $80.
Step-by-step explanation:
The simple interest formula is:
[tex]I=\frac{P\times r\times t}{100}[/tex]
It is provided that:
I = $80
P = $4,000
r = 5% p.a.
Compute the time required as follows:
[tex]I=\frac{P\times r\times t}{100}[/tex]
[tex]t=\frac{I\times 100}{P\times r}[/tex]
[tex]=\frac{80\times 100}{4000\times 5}\\\\=0.4\ \years\\\\=0.4\times 365\ days\\\\=146\ days[/tex]
Thus, it will take 146 days to earn an interest of $80.