The king and his messengers are travelling from the castle to the summer palace at a speed of 5 km/h. Along the way, the king sends a messenger back to the castle; an 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 with 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 ?

Trees grow on only one side of Park Avenue. There are 60 trees in total. Every second tree is a maple, and every third tree is either a linden or a maple. The remaining trees are birches. How many birches are there ? 

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 1 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 ? 

A thin colourfull ribbon is stuck on a transparent plastic cube as shown. 

Which of the following pictures does not represent the cube as seen from any perspective ?

Bob is going to visit four cities. He will start from and end up in his home town. The figure shows a map of the regions with the cities. The roads are only along the grid lines. Bob wants to make the trip as short as possible. Which route should Bob follow ?

A rectangle with a perimeter of 34 cm was divided into two smaller rectangles with perimeters 28 cm and 30 cm, as shown in the figure.

What is the area of the big rectangle ?

Which answer completes the addition tree ?

Nathalie wanted to build a large cube out of lots of small cubes. How many cubes are missing from the picture on the right that would be needed to build the large cube on the left ?

How far must Maria walk to reach her friend Bianca ?

Nick can turn right but not left on his bicycle. What is the least number of right tuns he must make in order to get from A to B ?

Anna, Bob and Chris are altogether 31 years old. How old will all three be altogether in three years time ?

In the following multiplication the same digit is used in each square:

Which digit must be used so that the calculation is correct ?