Question 906801

a+b=9,
0.3*a+0.45*b=0.35*9
a=9-b
0.3*(9-b)+0.45*b=3.15
2.7-0.3b+0.45*b=3.15
0.15*b=0.45
b=3
a=9-b
a=6  gal at 30%
b=3  gal at 45%
check
0.3*6+0.45*3=0.35*9
1.8+1.35=3.15
3.15=3.15
ok