其它
We left for a summer camp at $4:32$ PM and got to our destination at $6:11$ PM. How long did we travel? (Adapted from 2015 Math Kangaroo Problem, Level 1--2, Question \#24) 
Overseas Competition->Knowledge Point->Combinatorics->Time Problem
$6:11$ - $4:43$ = $1$ hour $39$ minutes 