Răspuns :
a = numar geologi
b = numar biologi
a) a = 2b
a - 20 = b + 18
2b - 20 = b + 18
2b - b = 18 + 20
b = 38
b) a = 38 x 2 = 76
a II -a saptamana:
a = 76 - 20 = 56
b = 38 + 18 = 56
a + b = 56 + 56 = 112
b = numar biologi
a) a = 2b
a - 20 = b + 18
2b - 20 = b + 18
2b - b = 18 + 20
b = 38
b) a = 38 x 2 = 76
a II -a saptamana:
a = 76 - 20 = 56
b = 38 + 18 = 56
a + b = 56 + 56 = 112