Răspuns:
Explicație pas cu pas:
a + b + c = 270
a = b + 2a/7
b = a - 2a/7 = 7a/7 - 2a/7 = 5a/7
b + c = a - 10
5a/7 + c = a - 10
c = a - 5a/7 - 10 = 7a/7 - 5a/7 - 10 = 2a/7 - 10
a + 5a/7 + 2a/7 - 10 = 270
7a/7 + 5a/7 + 2a/7 = 270 + 10
14a/7 = 280
2a = 280
a = 280 : 2 = 140 l in primul butoi
b = 5 x 140/7 = 100 l in al doilea butoi
c = 270 - 140 - 100 = 270 - 240 = 30 l in al treilea butoi