Which tile must be added to the picture so that the light grey area is as large as the black area ?

Henry and John started walking from the same point. Henry went 1 km north, 2 km west, 4 km south and finally 1 km west. John went 1 km east, 4 km south and 4 km west. Which of the following must be the final part of John’s walk so that he could reach the same point as Henry ?

The kangaroos A, B, C, D and E were sitting in this order, clockwise, around a circular table. When the bell rang, each kangaroo but one exchanged its position with a neighbour. The order of the kangaroos, clockwise, became A, E, B, D, C. Which kangaroo did not move ?

A square can be formed using four of these five pieces. Which one will not be used ?

A positive integer has three digits. The product of the digits is 135. What is the sum of the digits ?

In a restaurant, there are 16 tables, each with 3, 4 or 6 chairs. The tables with 3 or 4 chairs can accommodate 36 people. The restaurant can accommodate 72 people. How many tables are there with 3 chairs ?

The points A, B, C, D, E and F lie on a straight line in that order. We know that AF = 35, AC = 12, BD = 11, CE = 12 and DF = 16. What is the distance BE ?

Parisa sets her marbles in groups of equal size on the desk. After she arranged the marbles in groups of 3, she found that there were 2 marbles left. The she arranged the marbles in groups of 5, and again there were 2 marbles left. At least how many more marbles does she need so that there won’t be any left when she arranges them in groups of 3 and in groups of 5 ?

A plane takes off from Vienna at 11:00 am local time and arrives in Toronto at 1:00 pm local time. On average, it takes 8 hours for a plane of this type to fly this distance. What time is it in Toronto when it is 7:00 am in Vienna ?

What is the greatest number N, which, when divided by 7, has a remainder that is equal to the quotient ?

The king and his messengers are travelling from the castle to the summer palace at the speed of 5 km/h. Along the way, the king sends a messenger back to the castle; and one hour later, he sends back another messenger. If the messengers travel at a speed of 10 km/h, what is the time between their arrivals at the castle ?

The 3 x 3 x 3 cube in the picture is made of 27 small cubes.

How many small cubes do you have to remove to see the following result when viewing from the right, from above, and from the front ?

Andy made a playlist 5 songs ( A, B, C, D and E ). Song A is 3 minutes long, song B is 2 minutes and 30 seconds, song C is 2 minutes, song D is 1 minute and 30 seconds, and song E is 4 minutes. The songs play in this order in a continuous loop. If Andy left the house when song C was just starting, what song was playing when he got back home 1 hour later ?

Dan entered the numbers from 1 to 9 in the cells of a  3 x 3 table. He began by placing the numbers 1, 2, 3 and 4 as shown in the picture:

It so happened that for the number 5, the sum of the numbers in the adjacent cells ( having a common side ) was equal to 9. What is the sum of the numbers adjacent to the number 6 ?

Rabbit Vasya loves cabbage and carrots. In a day, he eats either 9 carrots, or 2 heads of cabbage, or I head of cabbage and 4 carrots. But some days he only eats grass. Over the last 10 days, Vasya ate a total of 30 carrots and 9 heads of cabbage. On how many of these 10 days did he eat only grass ?