Singapore time is $$7$$ hours ahead of London time. A plane took off from Singapore at $$05:00$$ of $$24$$th August and flew to London. When it landed in London, the clock there showed $$11:00$$ of $$24$$th August. How long did the flight take? 
Overseas Competition->Knowledge Point->Combinatorics->Time Problem->Time Calculation Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations