Mr turner bought stock for $15,000. if the value of the stock decreases 4% each year when will it be worth 80% of original price?

Step-by-step explanation:

we know that

In this problem we have a exponential function of the form

where

x is the time in years

f(x) is the value of the stock

a is the initial value

b is the base

r is the rate

b=(1-r)

we have

substitute

80% of original price is equal to

so

For f(x)=12,000 ------> Find the value of x

Apply log both sides