can someone help me thanks

1).
Zeus Industries bought a computer for $2538. It is expected to depreciate at a rate of 20% per year. What will the value of the computer be in 4 years? (Round to the nearest penny).

2).
A radio active isotope decays according to the exponential decay equation where t is in days.
Round to the thousandths place.
For the half life: The half life is the solution (t) of the equation :
a/2=ae^−3.392t.

Question

can someone help me thanks

1).
Zeus Industries bought a computer for $2538. It is expected to depreciate at a rate of 20% per year. What will the value of the computer be in 4 years? (Round to the nearest penny).

2).
A radio active isotope decays according to the exponential decay equation where t is in days. 
Round to the thousandths place. 
For the half life: The half life is the solution (t) of the equation : 
a/2=ae^−3.392t.