A good puzzle....crack it...
Four friends A, B, C, D
Need to cross d bridge..
They start on d same time to cross d bridge.
A maximum f 2 peoples can cross at a time..
It is night and they have just 1 lamp.
People that cross the bridge must carry the lamp to see the way..
A pair must walk together at the speed of slower person...
A: 1 minute to cross bridge
B: 2 minutes to cross
C: 7 minutes to cross bridge
D: 10 minutes to cross bridge
Now question is... "what is d total minimum time required by all 4 friends to cross the bridge....?
The person 1 & 2 will go first then the 2 will come back with the torch & then 5 & 10 both will go with the torch. The person 1 will come back with the torch and 2 & 1 will go to the other side. [ So the total will be 2+2+10+1+2=17mins.
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