Answer
Initial amount $a=1$
Rate of decay $r=12.5\%$
At $t=3,y\approx 0.7$
Work Step by Step
The given expression is
$\Rightarrow y=(\frac{7}{8})^t$
$\Rightarrow y=1(1-\frac{1}{8})^t$
The standard form of an exponential decay function is $y=a(1-r)^t$
Initial amount $a=1$
Rate of decay $r=\frac{1}{8}=12.5\%$
Substitute $3$ for $t$.
$\Rightarrow y=(\frac{7}{8})^3$
Evaluate the power.
$\Rightarrow y=0.669921875$
Round to the nearest tenth.
$\Rightarrow y\approx 0.7$.
