a:b = 2: 12/7
b:c = 1,5 : 7/8
c:d =7/3
++++++++++
12/7a = 2b
a= 2b*7/12 = 7/6 b
7/8 b= 3/2c
c=7/8b*2/3=7\12b
7d = 3c
d = 3/7 c
d=3/7 * 7/12 b =3|12= 1/4 b
a+b+c+d = 36
7/6 b +b+ 7/12b + 1/4b = 36
14/12b+b+7/12b+3/12b=36
b = 12
a=7/6 b=12 :6*7=14
c=7/12 b=12:12*7= 7
d=1/4b=12:4*1= 3