Can you solve it? Simple puzzles almost everybody gets wrong

Think Twice is the title of my new book (out on September 5) and it is also my advice for today’s puzzles.

1. Hello duckies

There are two ducks in front of two ducks, two ducks behind two ducks and two ducks in between. What is the minimum number of ducks?

2. Concentric conundrum

Imagine I am walking around a circle whose centre is Big Ben. For the purposes of this question, assume I can walk on water.

When the radius is 1 km, I will walk roughly 6.28km

When the radius is 100km , I will walk roughly 628km

When the radius is 10,000km, will I walk roughly 62,800km?

(The circumference of a circle is twice the radius times pi, which is 3.14 to two decimal places.)

3. Hanging by a string

A bottle of water hangs from the ceiling by a string. A handle hangs from the bottle by a piece of the same type of string, as below.

You pull the handle down. A string breaks. Which one?

a) the top one

b) the bottom one

c) they break at the same time

In each of these three questions the obvious answer is not the right one. (Or maybe it is, I might be double bluffing.)

I’m hoping you get them all wrong, of course. For a start, I have the headline to live up to. (Although TBF, when I was the only reader of this column it was true.) Are you up to the challenge?

I’ll be back at 5pm UK with the answers. Meanwhile, NO SPOILERS. Please discuss ducks.

Puzzles that seem very simple but that surprise us are – I think – the most fun kind of puzzle, and I have put 70 of my favourite examples in Think Twice. (Excluding the ones today.) There is something irresistible about a puzzle that subtly misdirects us, or that reveals something unexpected about the world.

The book is not out until September 5 but you can preorder already. If you are tempted, please, ahem, don’t think twice. Preorders really help give a book momentum. Help make it the Murdle of 2024!

Think Twice: Solve the simple puzzles (almost) everyone gets wrong by Alex Bellos (Square Peg, £12.99). To support the Guardian and Observer, order your copy at guardianbookshop.com . Delivery charges may apply.

Thanks to Fabio Ciuffoli, who first told me about the ducks, and Nikolai Andreev, who told me about the circles.

I’ve been setting a puzzle here on alternate Mondays since 2015. I’m always on the look-out for great puzzles. If you would like to suggest one, email me .