what base could be written in the blank to make the exponential function model 15% decay ? y= (____) ^t\12

The base of the function should be b = 0.85
The form of the function should be
[tex]y = a\times (b)^t[/tex]
Where,
A should be the initial amount
b decrease rate (b <1)
t be time (years, months, days)
Now
[tex]y = b^\frac{1t}{12}[/tex]
So, the value of the base should be
[tex]= (100-15)\div 100[/tex]
= 0.85
So, the function should be[tex]= 0.85^{(1\div 12)t[/tex]
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