Chapter 4

"What is that noise?" thought Ellie as a strange high-pitched, scratchy tone errupted from the electronic box that had always sat quietly in the corner. Inch by inch, a warm piece of paper emerged from the fax machine.

A set of black letters on a white background 110-100-32-4-32-11-5-17-15-10011-100-110-14-34-5-22-16-15-10100-120-12-100-5-23-25-1-12-10011-202-20-33-5-5-31-3-21-10-12-10-101-42-35-32-28-26

"Hmm," said Ellie, "This looks pretty basic to me. You'll have to try harder than that Mike!"

The image above contains a hidden question, please enter the answer below. If the answer is a number then please enter it to five decimal places.

Hint: The word "basic" is a clue. How could 110 represent one of the 26 possible letters of the alphabet?

To deter guessing without thinking, we ask that you also solve the following simple arithmetic problem before checking your answer:

If x = 3, y = 2 and z = 7, what is x × y - z?

This problem was first solved on Mon 5th February at 4:35:33pm

Alan Turing Cryptography Competition 2024 is organised by the The Department of Mathematics at The University of Manchester.
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