Răspuns :
Notam cu x si y nr.
x = 80 + 3y
80 + 3y + y = 2000
80 + 4y = 2000
4y = 2000 - 80 = 1920
4y = 1920
y = 1920 : 4
y = 480
a = 2000 - 480 = 1520
x = 80 + 3y
80 + 3y + y = 2000
80 + 4y = 2000
4y = 2000 - 80 = 1920
4y = 1920
y = 1920 : 4
y = 480
a = 2000 - 480 = 1520