we have the function
In this problem, we have an exponential decay function because the value of the base of the exponential function is less than 1
b=0.75
b< 1 -----> exponential decay function
Part b
Find out the annual percent decrease
b=0.75
b=1-r
0.75=1-r
r=1-0.75
r=0.25
r=25%
therefore
The annual percent decrease is 25%
Part c
For y=$50
substitute in the given equation
Solve for t
Apply log on both sides
x=4.8 years