# Blog

## My favourite book brainteaser

By David Shaw, 23 September 2022

Difficulty: Fun On my bookshelf, my favourite book is the third from the left, and it’s the seventh from the right. How many books are there on that shelf?

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## When clock hands meet brainteaser

By David Shaw, 24 August 2022

For an entire day, Ruth watched a dial clock, looking for when the hands met. She wrote down all the times they met. Which hour did the hands not meet?

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## Sneaker discount brainteaser

By David Shaw, 11 August 2022

Billie is really in to sneakers and is aiming to sell them for a profit. Work out if Billie made money, lost money, or sold the sneakers at their original price.

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## Two candles brainteaser

By David Shaw, 27 July 2022

Barry has 2 candles that are both 60 centimetres long. One will last for 1 hour, and the other will last for 2 hours. Barry lights both candles at the same time. Later, he blows them out at the same time. The next day, Barry realises that one of the candles is half the length of the other. Assuming they both burnt evenly, how long were they burning for?

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## Five makes 80 brainteaser

By David Shaw, 13 July 2022

Can you find 5 consecutive (counting upwards) numbers that add up to 80?

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## Two trains brainteaser

By David Shaw, 29 June 2022

Difficulty: Fun A fast passenger train leaves Sydney Central station, headed for Broken Hill. At the same time, a slow freight train, moving at only half the speed of the passenger train, leaves Broken Hill station, headed for Sydney Central. When they meet, which train is closer to Sydney?

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## Too many elevens brainteaser

By David Shaw, 16 June 2022

How many 1s does it take to write out the number eleven thousand, eleven hundred and eleven?

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## Paying the miller brainteaser

By David Shaw, 2 June 2022

A farmer goes to the local mill to get some wheat ground into flour. The miller doesn’t ask for money – instead, they take one tenth of the wheat as payment. If the farmer wants 100 kilograms (kg) of flour at the end, how much wheat should they bring?

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## Srinivasa’s street brainteaser

By David Shaw, 18 May 2022

Difficulty: Extreme! Srinivasa lives in a house on a short street, with houses on one side. The houses are numbered 1, 2, 3 and so on. He was practicing his addition when he noticed something strange.

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## Solo noughts and crosses brainteaser

By David Shaw, 5 May 2022

Difficulty: Tricky Mabel wanted to play noughts (O) and crosses (X), but she didn’t have anyone to play with. So she just took one go after another. Somehow, Mabel put Xs in 6 of the 9 squares without making a line of 3 Xs. Can you draw the board and work out which squares have […]

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