Monday Maths Madness 12

For anyone who is into Strictly Come Dancing, you will know that one of the celebrities is Johnny Ball. Johnny Ball is a TV personality from the 70s and 80s, and is known for popularising maths and science for children.

A little while ago, I can't remember exactly when, my mum bought me a book written by Johnny Ball. It is called Ball of Confusion, which is a collection of puzzles to do with maths, inspired by when he presented a puzzle on Zoe Ball's (his daughter) Radio 2 show. As Strictly just started this last weekend, I thought I would give a few puzzles from the book for you to ponder over.

1. Fumbling in the Dark

The lights have gone out - I said we should never trust wind farms - and I have to search my wardrobe in the dark for a pair of shoes and socks.

I have 3 pairs of shoes, 12 pairs of black and 12 pairs of brown socks.

How many of each do I need to take, to be sure I have a matching pair of each to wear?

2. Animal Farm

A farmer has 20 goats, 30 cows and 50 horses. How many horses would he have if you called the cows 'horses'?

3. Sum for simpletons

Look at this: 12 = 3 x 4.

Can you think of four other consecutive digits that do that?

4. An up and down kind of existence

A monk lives on a river bank in a valley. Once a week he must travel to the monastery at the top of the Lonely Mountain. He sets off at dawn, as the road is steep and long, and he arrives as the Sun sets. Next morning he has a lie in and leaves for home at 10am. As the road is downhill all the way, he arrives home at around 3pm.

What are the chances of the monk being at exactly the same point on the road, at exactly the same time on both days?

Answers on Wednesday! (Just to annoy my sister :P)