Răspuns :
D + A = 45
D = 27 + A
27 + A + A = 45
27 + 2 A = 45
2A = 45 - 27
2A = 18
A = 18 : 2
A = 9
Ana are 9 timbre
D = 27 + A
D = 27 + 9
D = 36
Dan are 36 timbre
verificam
36 + 9 = 45 timbre
D = 27 + A
27 + A + A = 45
27 + 2 A = 45
2A = 45 - 27
2A = 18
A = 18 : 2
A = 9
Ana are 9 timbre
D = 27 + A
D = 27 + 9
D = 36
Dan are 36 timbre
verificam
36 + 9 = 45 timbre