Question 902904
a+b=15,
0.1*a+0.5*b=0.3*15
a=15-b
0.1*(15-b)+0.5*b=4.5
1.5-0.1b+0.5*b=4.5
0.4*b=3
b=7.5
a=15-b
a=7.5 liter at 10% b=7.5 liter at 50%
check
0.1*7.5+0.5*7.5=0.3*15
0.75+3.75=4.5
4.5=4.5
ok