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 14
Оглавление29. Turbo the tortoise
Usain runs twice as fast as his mum. His mum runs five times as fast as his pet tortoise, Turbo. They all set off together for a run down the same straight path.
When Usain has run 100 metres, how far apart are his mum and Turbo the tortoise?
30. Rolling a cube
A cube is being rolled on a plane so it turns around its edges. Its bottom face passes through the positions 1, 2, 3, 4, 5, 6 and 7 in that order, as shown.
Which of these two positions were occupied by the same face of the cube?
31. Small change
My bus fare is 44p. If the driver can give me change, what is the smallest number of coins that must change hands when I pay this fare?
[The coins available are 1p, 2p, 5p, 10p, 20p, 50p, £1 and £2.]
32. Eight factors
The number 78 has exactly eight factors, including 1 and 78.
Which is the smallest integer greater than 78 that has eight factors?
33. A small sum
In the addition sum ‘TAP’ + ‘BAT’ + ‘MAN’, each letter must represent a different digit and no first digit is zero.
What is the smallest sum that can be obtained?
34. A circle on a grid
A circle is added to the grid shown.
What is the largest number of dots that the circle can pass through?
35. Numbers around a circle
Five integers are written around a circle in such a way that no two or three consecutive numbers have a sum that is a multiple of 3. Of the five numbers, how many are themselves multiples of 3?
