Question 906638
a+b=32,
0.37*a+0.12*b=0.28*32
a=32-b
0.37*(32-b)+0.12*b=8.96
11.84-0.37b+0.12*b=8.96
-0.25*b=-2.88
b=11.52
a=32-b
a=20.48  liter at 37%
b=11.52  liter at 12%

rounded
a=20.5  liter at 37%
b=11.5  liter at 12%
check
0.37*20.48+0.12*11.52=0.28*32
7.5776+1.3824=8.96
8.96=8.96
ok