Question

A limited-edition poster increases in value each year with an initial value of $18. After 1 year and an increase of 15% per year, the poster is worth $20.70. Write an equation that can be used to find the value, y, after x years? (Round money values to the nearest penny.)

Answer 1

y=18(1.15)^x

Explanation:

The general formula is

y=a(b)^x, where

a is the initial amount and

b is the growth (1+.15 in our case "an increase of 15%) or

decay rate (1 -.15 would be if the problem have said it decreased ).

x is the amount of time

y is the amount of money

20.70 = 18 (1.15)^1

The equation is:

y= 18(1.15)^x