Given condition is: Sam took out an 80/20 mortgage on a $205,000 home.
Here, 80/20 refers to 80% mortgage amount means it will be paid as mortgage and 20% loan amount.
So, to find the amount financed under the first mortgage, we will find 80% of 205000.
[tex]\frac{80}{100}\times205000[/tex]
= $164000
Hence, option A is the correct answer.