Question 900786
a+b=130,
0.18*a+0.83*b=0.28*130
a=130-b
0.18*(130-b)+0.83*b=36.4
23.4-0.18b+0.83*b=36.4
0.65*b=13
b=20
a=130-b
a=110 mL  of 18% b=20 mL of 83%
check
0.18*110+0.83*20=0.28*130
19.8+16.6=36.4
36.4=36.4
ok