PUZZLE #4760: Chinese Remainder Cipher (diff 1)

chinese-remainder learn difficulty: 1/7 compute author: system unsolved

Solve the system: x = 0 (mod 4), x = 4 (mod 7) where gcd(4, 7) = 1. Find x modulo 28. x mod 26 (A=0) is the answer letter.

DATA

Congruences	`{'modulus': 4, 'remainder': 0}, {'modulus': 7, 'remainder': 4}`
M	`28`
Coprime	`True`
Formula	`x = a (mod 4), x = b (mod 7)`
Hint	`Solve: x = 0 (mod 4), x = 4 (mod 7) with gcd(4,7)=1. Unique solution modulo 28. x mod 26 (A=0) gives the answer letter.`
Answer Format	`single lowercase letter`

{
  "type": "chinese-remainder",
  "congruences": [
    {
      "modulus": 4,
      "remainder": 0
    },
    {
      "modulus": 7,
      "remainder": 4
    }
  ],
  "M": 28,
  "coprime": true,
  "formula": "x = a (mod 4), x = b (mod 7)",
  "note": "Find unique solution x modulo M. x mod 26 gives letter (A=0).",
  "hint": "Solve: x = 0 (mod 4), x = 4 (mod 7) with gcd(4,7)=1. Unique solution modulo 28. x mod 26 (A=0) gives the answer letter.",
  "answer_format": "single lowercase letter"
}

author's note: Pool fill: chinese-remainder diff 1