Answer
Initial amount $a=1$
Rate of growth $r=80\%$
$p(5)=18.9$
Work Step by Step
The given expression is
$\Rightarrow p(t)=1.8^t$
$\Rightarrow p(t)=1(1.8)^t$
$\Rightarrow p(t)=1(1+0.8)^t$
The standard form of an exponential growth function is
$y=a(1+r)^t$
Initial amount $a=1$
Rate of growth $r=0.8=80\%$
Substitute $5$ for $t$.
$\Rightarrow p(5)=1.8^5$
Evaluate the power.
$\Rightarrow p(5)=18.89568$
Round to the nearest tenth.
$\Rightarrow p(5)=18.9$
