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How many of these GCHQ puzzles can you solve?

If you listen to The Infinite Monkey Cage, you’re probably pretty smart, but how good are you at puzzles?

To welcome the Radio 4 show to GCHQ, the intelligence agency famed for their problem solving set presenters Brian Cox and Robin Ince this test.

How will you do?

Here's a relatively easy one to start…

1. What is the next letter in the sequence: M, V, E, M, J, S, U, ?

N. The sequence is the first letter of each of the planets going out from the sun, ending with Neptune.

2. Brian and Robin went to the cinema. In cryptic crossword clue terms, the film they saw was £6,000 [6,7]. What was the film?

Twelve Monkeys. Monkey is slang for £500. 12 x £500 = £6,000.

3. Which word does not belong in the following sentence? “Will son of Nazareth ferry cousin’s kid? He knows you will.”

Hint: saying it out loud will help.

The sentence when read out could be interpreted as Wilson, of Nazareth, Ferry, Cousins, Kidd, Eno, Sewell. So the odd one out is (Robin) Cousins, as the rest are all famous Brians.

4: What’s the missing 3rd entry in this sequence? I:Sheet, XXV:Quire, ?, M:Bundle.

The missing entry is D:Ream (Brian Cox’s former band). These are metric paper quantity names, with the number of sheets in each in Roman numerals. There are 500 sheets in a Ream, and 500 = D in Roman numerals.

5. What do you get if you blend three measures of argon, two bits of gold, two of carbon and one of sodium together with top grade artificial intelligence?

If you translate the sentence into symbols you get:

  • 3 x Argon = ARARAR, 2 x Gold = AUAU, 2 x Carbon = CC, 1 x Sodium = NA, top grade = A, Artificial Intelligence = AI
  • Adding all these letters together you get ARARARAUAUCCNAAAI which can be rearranged as ARAUCARIA ARAUCANA which is the Latin name for the Monkey Puzzle Tree

6. Brian Cox should have no trouble with this but can you work out which D:Ream songs these are?

  • Phil Taylor (from nothing earthly)


  • An ancient Sumerian city-state in Mesopotamia is comparable to sliced bread

  • 1992 Clint Eastwood film

  • Nothing will deteriorate in the future

  • The Power (Of all the Love in the World)
  • Gods in the Making
  • UR The Best Thing
  • Unforgiven
  • Things Can Only Get Better

And finally, here’s a puzzle for fans of The Infinite Monkey Cage...

7. A computer scientist has 57,005 strawberries. Does he give them to Brian or Robin?

He gives them to Robin, as Brain does not believe in dead strawberries. 57,005 is DEAD in hexadecimal.

The Infinite Monkey Cage has clocked up 100 editions. You can listen to them all online or download the podcasts.

Follow GCHQ on Twitter for more tough puzzles.