As per the problem,
Rhonda bought a new laptop for $800.
The laptop depreciates, or loses, 20% of its value each year.
The value of the laptop at a later time can be found using the formula

Here we have
P=$800
r=20%=0.20
t=2 years
Substitute the values in equation (1) we get

The laptop be worth in two years will be $512.