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SOPHIA Project Anonymous 11/20/2025 (Thu) 14:27 [Preview] No. 319
Hello,
We are looking for individuals to join a team dedicated to a confidential project. To submit your application, you must first solve the following logical puzzle. Your answer will be a four-digit code. Include this code together with a way to contact you. Only applications with the correct code will be considered. Puzzle: The access code is a four-digit number ABCD with the following properties:

1) All four digits A, B, C and D are different, and A ≠ 0.
2) The number ABCD is a prime number.
3) The number obtained by reversing the digits, DCBA, is also prime.
4) The sum of the digits is 20: A + B + C + D = 20.
5) The two middle digits, BC, form a two-digit prime number.
6) The first and last digits, AD, read together as a two-digit number, also form a prime number.
What is the code ABCD?

Selected candidates will receive further information soon.
Best regards, The Sophia Team Project


Curious 05/07/2026 (Thu) 14:29 [Preview] No.328 del
>>319
What does the project pertain to?


Abyssblade67 05/24/2026 (Sun) 21:43 [Preview] No.330 del
La clave es notar primero una propiedad importante:

Como ABCD y DCBA son primos de 4 cifras, ni A ni D pueden ser pares ni 5.
Además, BC es un primo de dos cifras. Todo primo de dos cifras (excepto 2) es impar, así que C debe ser impar.
La suma total es 20 (par). Si C es impar y B+C debe ser par, entonces B también es impar.

Por lo tanto, los cuatro dígitos son impares y distintos.

Los únicos cuatro dígitos impares distintos que suman 20 son:

1, 3, 7, 9

Ahora buscamos un orden que cumpla todas las condiciones.

Probando combinaciones válidas:

BC=19 es primo.
AD=73 es primo.
El número completo:
7193

es primo, y su reverso:

3917

también es primo.

Entonces el código correcto es:

7193



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