Thirteen friends join a sport club together. Eight of them play football, six of them play tennis and five of them play badminton. If everyone plays sport but no one plays only two kinds of sport, how many people play all three kinds?

Alice said to her mother, “If I reverse the two digits of my age, I will get your age”. Her mother said, “Tomorrow is my birthday, and my age will then be three times yours”. It is known that their birthdays are not on the same day. How old is Alice?

Forty students from five grades brought 50 candies for the “Trick or Treat” game in a Halloween party. It is known that students from the same grade brought an equal number of candies, while students from different grades brought different numbers of candies. How many students brought exactly one candy? 

Two of my digits are odd, but my units digit is even. The sum of my digits is 14. I’m between 567 and 599 and I' m not 590. What number am I? 

Find the sum of all 2 – digit numbers such that each number is 13 times its tens digit ?

A boy weighed his twin cat and two identical hat together and got 2200g. He then weighed one hat and a 10kg -  weight and got 10450g. What was the weght of one cat ?

Emily orders one food and one drink from the menu. How many different ways can she order?

Oranges are sold in baskets of three at the cost of 4dollars each, or baskets of five at the cost of 5 dollars each. What is the smallest cost at which John can buy 158 oranges?

Anna, Brat and Cindy had $635 altogether. Anna spent $\frac{1}{4}$of her money and Brat spent thrice the amount Anna spent. Cindy spent $50. Iff they had the same amount of money left, how many dollars did Anna have at first ?

Using each of the digits 1, 2, 3, 4 and 5 exactly once to from 5 – digit numbers. How many are divisible by 12 ?

The figure below is made up of four identical squares and one rectangle. If he perimeter of the figure is 64cm and the perimeter odd the rectangle is 16 cm, then what is the area of each square?

Ten numbers were written on 10 cards as follow :

Mr. Zack chose 4 of these cards to form a 4 – digit odd number. He stood in front of a mirror and looked at it up – side – down through the mirror. He saw a new number wass 720 larger than the original one, then what is the original number ?

How many 4 – digit numbers contain the digit 2, or the digit 3 or both ?

The value of expression: A = $\frac{1}{2016}+\frac{3}{2016}+\frac{5}{2016}+...+\frac{2015}{2016}$   is ..................

The area of the following rhomus is ............