GIVE YOUR MIND MUSCLES A WORKOUT

AS I explained in Saturday’s Mail, I know of no better mental exercise than simply to apply my trained-memory techniques. But to break up the process, every so often I also like to throw in a riddle, a puzzle — a ‘thought provoker’. Practise these intermittently to exercise your brain. You’ll find you have fun with them — just as you’ll have fun with my memory training systems.

1. SPECIAL MIND-POWER EXERCISE

THIS will take a bit of thinking and experimenting. That, as you know by now, is the whole point. The trying to work it out — the thinking and the experimenting — is the mental exercise. OK, then: Chickens cost 50p each. Ducks cost £3 each. Turkeys cost £10 each. The problem is: You want to buy exactly 100 birds and spend exactly £100. How many of each should you buy?

2. SPECIAL MIND-POWER EXERCISE

I’VE never yet had anyone give me the answer to this one. Yet it’s a fairly easy problem to solve, if you look at it the right way. The number four is unique. In all of ‘numberdom’, there is no other number about which you can make this claim. Your task is to see if you can work out its uniqueness. I assure you this is not a trick question — it has a legitimate answer.

3. SPECIAL MIND-POWER EXERCISE

LOOK at these four prices: £3.16 £1.20 £1.25 £1.50

Now look again, think about them, work with them, and try to work out why they are unique, or what’s unusual about them.

If you don’t want a hint, don’t read any further or look below. (Clue: These are prices of items I found in a 7-Eleven Store.)

ANSWERS 1. 94 chickens at 50p each, £47. 1 duck at £3. 5 turkeys at £10 each, £50. 2. in all of ‘numberdom’, the only number that tells you how many letters it is spelled with is FOUR. 3. The fact i found these in a 7-Eleven store is the answer. Add the four prices and they come to £7.11. Multiply them and it’s £7.11.