Crossing the bridge Puzzle
Crossing the Bridge Puzzle
4 people want to cross it before it will collapse. It is a dark night and there is only one torch between them.
Only two people can cross at a time.
“A” takes a minute to cross.
“B” takes 2 minutes.
“C” takes 5
and “D” takes 10 minutes
How do they all cross before the bridge collapses?
Time in which bridge will collapse = 17 mins
Number of people wants to cross the bridge = 4 people
Number of torch they have = 1
Time take by A to cross the bridge = 1 minute
Time taken by B to cross the bridge = 2 minutes
Time taken by C to cross the bridge = 5 minutes
Time taken by D to cross the bridge = 10 minutes
Move Time A & B Cross with torch 2 min A return with torch 1 min C & D Cross with torch 10 min B return with torch 2 min A & B cross with torch 2 min
Total time 17 min
Time left before the bridge collapse = 14 mins
Time left before the bridge collapse = 2 mins
Hence A, B, C ,and D all four will cross the bridge within 17 mins.