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.
The correct answer ic C)12
12 oz for 2.68 = .22 per unit
16 oz for 2.49 = .16 per unit
the 16 oz for 2.49 is your better deal
No it does not change it is a imaginary like used to move a figure. Nor does it move when it is rotated