Share the coins

Share the coins

by | Dec 8, 2018 | english

There is a bag with 99 coins to be distributed among n persons, with the following rule: the first person takes 1, 2 or 3 coins. The following ones take, each at their time, one coin more or one coin less than the previous one. What is the smallest number of persons...
Two sets of balls

Two sets of balls

by | Dec 8, 2018 | english

We have n balls numbered from 1 to n. For which values of n can you divide the balls in 2 sets so that the sum of the numbers in each set is the same. Go to the solution. 
Two nails holding a necklace

Two nails holding a necklace

by | Dec 8, 2018 | english

You want to hang a necklace to two nails in a way If both nails are there the necklace would hangIf you remove either one of the two nails the necklace would fall NOTE: It is not a matter of balancing weight. It is all about how you wind the chain around the nails. Go...

Crossing a bridge

by | Dec 8, 2018 | english

Four friends need to cross a bridge. They start on the same side of the bridge. A maximum of two people can cross at any time. It is night and they have just one lamp. People that cross the bridge must carry the lamp to see the way. A pair must walk...