Question 1131591
the mean is 1/26.23=0.0381
wait more than x minutes is e^(-0381x)=0.23
take ln both sides so that -0.0381x=ln(0.23)=-1.47
therefore, x=1.47/0.0381=38.5741 minutes ANSWER

waiting fewer than x minutes is 1-e^(-0.0381*x) and that is 0.47. 
-e-(0.0381x)=-0.53
e^(-0.0381x)=0.53, this is waiting longer than x minutes
ln both sides and -0.0381x=-0.635
x=16.6667 minutes or 50/3 minutes ANSWER
check that 1-e^(-0.0381*16.6667)=1-e^(-0.6350)=1-0.5299=0.47.

{{{graph(300,300,-2,50,-1,1.5,e^(-0.0381x))}}}