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Brain Twister #12: Factorial factory

Can you solve this week’s logic puzzle? Plus our quick quiz and the answer to last week’s problem

By New Scientist

20 March 2024

New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

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#12 Factorial factory

Set by Mary Ellis

Mathematicians write 9! to represent the number “9 factorial”, which means 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 362,880.

How many zeros will 10! end with?

How many zeros will 25! have at the end? (Careful, the answer isn’t five.)

How many zeros will 1066! finish with?

Solution next week

#11 Club shuffling

Solution

If the players are A, B, C and D then the possible games are: AB vs CD, AC vs BD and AD vs BC. So there are three games in total.

If A wins all their…

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