Puzzle for November 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 = 27 eq.2) E = C + D eq.3) F = B + C eq.4) A = C + E eq.5) B = A + C + E eq.6) D + E = A + C

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 A with C + E (from eq.4): D + E = C + E + C which becomes D + E = 2×C + E Subtract E from each side of the equation above: D + E - E = 2×C + E - E which makes D = 2×C


  

Hint #2


In eq.2, replace D with 2×C: E = C + 2×C which makes E = 3×C


  

Hint #3


In eq.4, substitute 3×C for E: A = C + 3×C which makes A = 4×C


  

Hint #4


Substitute 4×C for A, and 3×C for E in eq.5: B = 4×C + C + 3×C which makes B = 8×C


  

Hint #5


Substitute 8×C for B in eq.3: F = 8×C + C which makes F = 9×C


  

Solution

Substitute 4×C for A, 8×C for B, 2×C for D, 3×C for E, and 9×C for F in eq.1: 4×C + 8×C + C + 2×C + 3×C + 9×C = 27 which simplifies to 27×C = 27 Divide both sides of the above equation by 27: 27×C ÷ 27 = 27 ÷ 27 which means C = 1 making A = 4×C = 4 × 1 = 4 B = 8×C = 8 × 1 = 8 D = 2×C = 2 × 1 = 2 E = 3×C = 3 × 1 = 3 F = 9×C = 9 × 1 = 9 and ABCDEF = 481239