Simple interest formula:
[tex]I=prt[/tex]
where [tex]I[/tex]=interest, [tex]p[/tex]=principal (how much you put in at first), [tex]r[/tex]=rate as a decimal, and [tex]t[/tex]=number of years.
Let's plug in what we're given.
[tex]I=350\times0.05\times4[/tex]
Calculate it out...
[tex]\boxed{I=70}[/tex]
The interest earned is $70.00.
