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Puzzles

One activity that many of our members enjoy is puzzling! You can test yourself for fun with our brainteasers. Our quizzes and conundrums are updated regularly, so do check back on the page for the latest content, and if you get really good at them, why not find out what your IQ is by booking a Mensa Supervised IQ Test?

25/9/25 – Fish Tank

Dave spends exactly £80 buying new tropical fish for his tank.

  • Clown Loaches cost £9 each
  • Neon Tetras cost £4 each
  • Angel Fish cost £10 each

 

In total he buys TEN fish, including at least one of each variety. How many Neon Tetras did Dave buy?

Puzzle courtesy of Mensa member Peter Hooton

  • Show Answer

3

9c + 4t + 10a = 80

c + t + a = 10 ……… 4c + 4t + 4a = 40

5c + 6a = 40

6a = 40 – 5c

6a = 5 (8 – c)

a is multiple of 5, therefore a = 5, c = 2, t = 3

Puzzles for business use

We are also able to supply puzzle content to businesses, tailored to your needs. This can range from one-off media projects for marketing campaigns and content for newspapers, magazines and company websites, to long-running partnerships and licensing agreements.

Find out more by contacting our marketing team, via: communications@mensa.org.uk