So A+A+4+C+C× 4 = 55, and 5 C +2 A +4=55.
5 c is a multiple of 5. 2 A +4 must be a multiple of 10, and if it is even, it is ≤50.
So a may be equal to 23, 18, 13, 8, 3.
When A =23, B =27, C = 1, D =4.
When A = 18, B =22, C =3, D = 12.
When A = 13, B = 17, C =5, D =20.
When A = 8, B = 12, C =7, D =28.
When A = 3, B = 7, C =9 and D =36.
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