Puzzle for September 7, 2021  ( )

Scratchpad

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

eq.1) A + B + C + D + E + F = 32 eq.2) F = A + B eq.3) B + E = C eq.4) C + E = A – C eq.5) F – C = D – B – E eq.6) D + F – A = A + E

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

Scratchpad

 

Help Area

Hint #1


In eq.5, substitute (B + E) for C (from eq.3): F – (B + E) = D – B – E which becomes F – B – E = D – B – E Add B and E to both sides of the above equation: F – B – E + B + E = D – B – E + B + E which simplifies to F = D


  

Hint #2


Substitute D for F in eq.2: D = A + B which means eq.2a) F = D = A + B


  

Hint #3


In eq.6, substitute A + B for D and F (from eq.2a): A + B + A + B – A = A + E which becomes A + 2×B = A + E Subtract A from each side of the equation above: A + 2×B – A = A + E – A which makes 2×B = E


  

Hint #4


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


  

Hint #5


In eq.4, replace C with 3×B, and E with 2×B: 3×B + 2×B = A – 3×B which becomes 5×B = A – 3×B Add 3×B to both sides of the above equation: 5×B + 3×B = A – 3×B + 3×B which makes 8×B = A


  

Hint #6


Substitute 8×B for A in eq.2a: F = D = 8×B + B which makes F = D = 9×B


  

Solution

Substitute 8×B for A, 3×B for C, 9×B for D and F, and 2×B for E in eq.1: 8×B + B + 3×B + 9×B + 2×B + 9×B = 32 which simplifies to 32×B = 32 Divide both sides of the above equation by 32: 32×B ÷ 32 = 32 ÷ 32 which means B = 1 making A = 8×B = 8 × 1 = 8 C = 3×B = 3 × 1 = 3 D = F = 9×B = 9 × 1 = 9 E = 2×B = 2 × 1 = 2 and ABCDEF = 813929