Step 1 :\(A = P(1 + r)^t\)
Step 2 :\(2P = P(1 + 0.5)^t\)
Step 3 :\(t \approx 1.7\) years to double
Step 4 :\(3P = P(1 + 0.5)^t\)
Step 5 :\(t \approx 2.7\) years to triple
Step 6 :\(4P = P(1 + 0.5)^t\)
Step 7 :\(t \approx 3.4\) years to quadruple
Step 8 :\(P(t) = P_0(1 + r)^t\)
Step 9 :\(2(158000) = 158000(1 + 0.0825)^t\)
Step 10 :\(t \approx 8.7\) years to double population
Step 11 :\(3(158000) = 158000(1 + 0.0825)^t\)
Step 12 :\(t \approx 13.9\) years to triple population
Step 13 :\(4(158000) = 158000(1 + 0.0825)^t\)
Step 14 :\(t \approx 17.5\) years to quadruple population
Step 15 :\(\boxed{1.7}\) years for principal to double
Step 16 :\(\boxed{2.7}\) years for principal to triple
Step 17 :\(\boxed{3.4}\) years for principal to quadruple
Step 18 :\(\boxed{8.7}\) years for Allenwood population to double
Step 19 :\(\boxed{13.9}\) years for Allenwood population to triple
Step 20 :\(\boxed{17.5}\) years for Allenwood population to quadruple