John decides to get the vaccine for COVID.  He has to wait 20 minutes for the first dose.  The second dose has a wait time half as long.  How long was the total wait time?
The second dose had a wait time of 20/2=<T>divide(20, 2)=10.0 minutes
So the total wait time is 20+10=<T>add(20, 10)=30 minutes
