Puzzle for February 6, 2023  ( )

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Find the 6-digit number ABCDEF by solving the following equations:

eq.1) A + B + C + D + E + F = 26 eq.2) F = B + C eq.3) C = A + B eq.4) D = B + F eq.5) E = A + D eq.6) B + D = A + E

A, B, C, D, E, and F each represent a one-digit non-negative integer.

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Hint #1


In eq.6, replace E with A + D (from eq.5): B + D = A + A + D which becomes B + D = 2×A + D Subtract D from each side of the equation above: B + D - D = 2×A + D - D which makes B = 2×A


  

Hint #2


In eq.3, replace B with 2×A: C = A + 2×A which makes C = 3×A


  

Hint #3


In eq.2, substitute 2×A for B, and 3×A for C: F = 2×A + 3×A which makes F = 5×A


  

Hint #4


Substitute 2×A for B, and 5×A for F in eq.4: D = 2×A + 5×A which makes D = 7×A


  

Hint #5


Substitute 7×A for D in eq.5: E = A + 7×A which makes E = 8×A


  

Solution

Substitute 2×A for B, 3×A for C, 7×A for D, 8×A for E, and 5×A for F in eq.1: A + 2×A + 3×A + 7×A + 8×A + 5×A = 26 which simplifies to 26×A = 26 Divide both sides of the above equation by 26: 26×A ÷ 26 = 26 ÷ 26 which means A = 1 making B = 2×A = 2 × 1 = 2 C = 3×A = 3 × 1 = 3 D = 7×A = 7 × 1 = 7 E = 8×A = 8 × 1 = 8 F = 5×A = 5 × 1 = 5 and ABCDEF = 123785