Answer:
[tex]y = 18 * 1.15^x[/tex]
Step-by-step explanation:
Given
[tex]a = 18[/tex] --- initial
[tex]r =15\%[/tex] -- rate
Value after a year = $20.70
Required
Expression to calculate its value after y years
This is calculated using:
[tex]y = ab^x[/tex]
Where
[tex]b=1 +r[/tex]
Substitute [tex]r =15\%[/tex] in [tex]b=1 +r[/tex]
[tex]b = 1 + 15\%[/tex]
[tex]b = 1 + 0.15[/tex]
[tex]b = 1.15[/tex]
Substitute [tex]b = 1.15[/tex] and [tex]a = 18[/tex] in [tex]y = ab^x[/tex]
[tex]y = 18 * 1.15^x[/tex]
