Taking the 3 solutions as 3 different terms, we can create an equation as follows:
Solution 1 : 10mL with 20% acid
Solution 2 : 30mL with x% acid
Solution 3 : 40mL with 32% acid
Since solution 1 + solution 2 = solution 3, let us substitute the given values we have:
10(0.2) + 30(x) = 40(0.32)
2 + 30x = 12.8
To solve for the unknown concentration x, we subtract 2 from both sides:
2 + 30x - 2 = 12.8 - 2
30x = 10.8
Dividing both sides by 30:
30x/30 = 10.8/30
x = 0.36
Therefore the unknown solution is 36% acid.
