Test your IQ
There was a depository of gold bars at the centre of a blank vault,which was protected by seven concentric,concrete walls with exactly one door in each wall.Each door was protected by a guard.One day,a man made a deal with the first guard,which allowed him to pass on the condition that he would give the guard half of the gold bars that he was carrying with him. However, the guard was required to return one gold bar to him.He made the same deal with the remaining guards at each door.How many gold bars should he have originally taken if he ended up getting two for himself?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
After the last door, the man has 2 gold bars left. This means that after the last guard gave him the 1 gold bar, he has 2 gold bars left. This means that before that guard gave him the 1 gold bar, he had 1 bar left. This 1 bar is how much he had after he'd given the (same) guard half of what he previously had, meaning that he had 2 bars before he encountered this guard. The same situation goes for all 7 of the guards. Therefore, the man started with 2 gold bars.