A chemist has 30%, 40 % and 80 % acid solutions. All three were to be mixed to make 4.00 x 102 L of 38% acid solution but a mistake was made and the amounts of 30% and 80 % were reversed. The result was 4.00 X 102 L of 65 % acid solution. What were the amounts of each solution supposed to be for the correct formula?

acid in 400L 38% = 152

acid in 400L 65% = 260

if the 3 solutions were wanted in the amounts a,b,c respectively, then

a+b+c = 400
.3a + .4c + .8b = 260
.3a + .4b + .8c = 152

a = 340/3
b = 835/3
c = 25/3

check my results to make sure they fit the conditions.