Math Archive

18 Mar 2017

Dinner bill

Three friends at a restaurant should pay 30 dollars together for the same 3 meals. They paid their bill but when waiter passed the money to his manager he told him that they should pay only 25
11 Mar 2017

Creaky Bridge

There is a creaky bridge in the forest which can hold only 2 people maximum at the same time. You and your 3 friends reached such bridge in the middle of the night and have to cross
18 Feb 2017


Math teacher wanted to measure quiz time in an original way. Thus he brought two sandglasses to the class, one which measured exactly 7 minutes and one which measured exactly 11 minutes. How did he know when
14 Feb 2017

Five-card magic trick

Imagine you and your friend are going to perform a magic trick with standard deck of 52 cards. Your friend will be the magician and you will be his “randomly” selected person from the audience, but no
31 Jan 2017

Complete triangle

Complete the last row in a triangle:   Hint Result    
21 Jan 2017

Boxes with marbles

Imagine you have 3 boxes with marbles (you cannot see what is in them). Each box has a label saying what is in it. One box is full of blue marbles, second box is full of red