Читать книгу The Ultimate Mathematical Challenge: Over 365 puzzles to test your wits and excite your mind - Литагент HarperCollins USD, F. M. L. Thompson - Страница 12
Оглавление22. Pings and pongs
Five pings and five pongs are worth the same as two pongs and eleven pings.
How many pings is a pong worth?
23. How many sides?
A single polygon is made by joining dots in the grid with straight lines, which meet only at dots at their end points. No dot is at more than one corner. The diagram shows a five-sided polygon formed in this way.
What is the greatest possible number of sides of a polygon formed by joining the dots using these same rules?
24. A tennis club
Three-quarters of the junior members of a tennis club are boys and the rest are girls. What is the ratio of boys to girls among these members?
25. Rectangles in a square
Five equal rectangles are placed inside a square with side length 24 cm, as shown in the diagram.
What is the area in cm2 of one rectangle?
26. The absent present
Four children bought a birthday present for their father. One of the children hid the present. When their mother asked them who had hidden the present, the four children made the following statements:
Alfred: ‘It was not me!’
Benjamin: ‘It was not me!’
Christian: ‘It was Daniel!’
Daniel: ‘It was Benjamin!’
It turned out that exactly one of them did not tell the truth.
Who hid the present?
27. Professor Brainstorm’s clock
Professor Brainstorm’s clock gains 16 minutes every day.
After she has set it to the correct time, how many days pass before it next tells the correct time?
28. What is n?
You are given that n is a positive integer with the property that when we add n and the sum of its digits, we obtain the number 313.
What are the possible values of n?
