Răspuns:
Explicație pas cu pas:
12.
2a = 3b = 6c = k
a = k/2
b = k/3
c = k/6
a + b + c = 30
k/2 + k/3 + k/6 = 30
3k/6 + 2k/6 + k/6 = 30
6k/6 = 30
k = 30
a = 30/2 = 15
b = 30/3 = 10
c = 30/6 = 5
____________________
13.
6a = 9b = 12c = k
a = k/6
b = k/9
c = k/12
a + b + c = 52
k/6 + k/9 + k/12 = 52
6k/36 + 4k/36 + 3k/36 = 52
13k/36 = 52
k = 36*52/13 = 144
a = 144/6 = 24
b = 144/9 = 16
c = 144/12 = 12