Литагент HarperCollins - The Ultimate Mathematical Challenge - Over 365 puzzles to test your wits and excite your mind

5. One less than a multiple of eleven (3)

8. A power of nine (4)

9. The mean of 3 DOWN, 7 ACROSS, 13 DOWN, 17 ACROSS and 27 DOWN (2)

11. Ninety-one less than 10 ACROSS (2)

13. The sum of the squares of the digits of 23 ACROSS (2)

14. A factor of 4567 (4)

16. The difference between 11 DOWN and 3 DOWN (2)

18. The square root of 8 DOWN (2)

20. The highest common factor of 10 ACROSS and 24 DOWN (2)

21. The total number of days in a year in the months whose names do not contain the letter A (3)

22. A prime that is ten less than a cube (3)

24. A square multiplied by five; the product of its digits is 40 (3)

27. A triangular number that is the sum of two prime numbers that differ by eight (2)

[SOLUTION]

Week 25

169. Non-factors of 720

Sam starts to list in ascending order every positive integer that is not a factor of 720.

Which is the tenth number in her list?

[SOLUTION]

170. What size is JMO?

In the diagram, JK and ML are parallel. JK = KO = OJ = OM and LM = LO = LK .

Find the size of the angle JMO .

[SOLUTION]

171. Amrita’s numbers

Amrita has written down four whole numbers. If she chooses three of her numbers at a time and adds up each triple, she obtains totals of 115, 153, 169 and 181.

What is the largest of Amrita’s numbers?

[SOLUTION]

172. Where do the children come from?

Five children, boys Vince, Will and Zac, and girls Xenia and Yvonne, sit at a round table. They come from five different cities: Aberdeen, Belfast, Cardiff, Durham and Edinburgh. The child from Aberdeen sits between Zac and the child from Edinburgh. Neither of the two girls is sitting next to Will. Vince sits between Yvonne and the child from Durham. Zac writes to the child from Cardiff.

Where does each child come from?

[SOLUTION]

173. Find four integers

Find four integers whose sum is 400 and such that the first integer is equal to twice the second integer, three times the third integer and four times the fourth integer.

[SOLUTION]

174. Bradley’s Bicycle Bazaar

In the window of Bradley’s Bicycle Bazaar there are some unicycles, some bicycles and some tricycles. Laura sees that there are seven saddles in total, thirteen wheels in total and more bicycles than tricycles.

How many unicycles are in the window?

[SOLUTION]

175. Liz and Mary’s problems

Liz and Mary compete in solving problems. Each of them is given the same list of 100 problems. For any problem, the first of them to solve it gets 4 points, while the second to solve it gets 1 point. Liz solved 60 problems, and Mary also solved 60 problems. Together, they got 312 points.

How many problems were solved by both of them?

[SOLUTION]

Week 26

176. Edinburgh to London

Travelling by train from Edinburgh to London, I passed a sign saying ‘London 150 miles’. After seven more miles, I passed another sign saying ‘Edinburgh 250 miles’.

How far is it by train from Edinburgh to London?

[SOLUTION]

Текст предоставлен ООО «ЛитРес».

Прочитайте эту книгу целиком, купив полную легальную версию на ЛитРес.

Безопасно оплатить книгу можно банковской картой Visa, MasterCard, Maestro, со счета мобильного телефона, с платежного терминала, в салоне МТС или Связной, через PayPal, WebMoney, Яндекс.Деньги, QIWI Кошелек, бонусными картами или другим удобным Вам способом.