Answer:
[tex]57.2\ g[/tex]
Step-by-step explanation:
In this problem we have a exponential function of the form
[tex]f(x)=a(b^x)[/tex]
where
f(x) is the remaining mass of the element in grams
x is the time in minutes
a is the initial value (y-intercept of the exponential function)
b is the base
r is the rate
[tex]b=(1+r)[/tex]
In this problem we have
[tex]a=210\ g[/tex]
[tex]r=-8.3\%=-8.3/100=-0.083[/tex] ---> is negative because is a decay's rate
[tex]b=(1-0.083)=0.917[/tex]
substitute
The exponential function is equal to
[tex]f(x)=210(0.917^x)[/tex]
For x=15 minutes
substitute in the function
[tex]f(x)=210(0.917^{15})[/tex]
[tex]f(x)=57.2\ g[/tex]
