Let the unpaid balance amount be represented by = x
Rate of interest is = 1.9 %
Stephen paid an amount of = $21.77
This 21.77 is the amount of 1.9% of x
So, [tex]\frac{1.9x}{100}=21.77[/tex]
[tex]1.9x=2177[/tex]
x = 1145.789 or rounding it we get 1145.79
So, the unpaid balance of Stephen Joyce is $1145.79