Let x% be the salt concentration of first solution.
Then in 8ml, amount of salt = 
Given that to this 8ml solution, 11ml solution of a 47% salt solution is mixed.
amount of salt in 11ml of 47% salt solution is
= 
So, total amount of salt in new mixture = 
But given that this new solution is a 43% salt solution.
Hence amount of salt in new mixture of (8+11)=19ml solution of 43% salt solution is 
Hence 
8x+517 = 817
8x=817-517 = 300
x= 300/8 = 37.5
Hence the salt concentration in the first solution is 37.5%
Answer:
I'm so sorry I can't help but you can try and use math-way to answer anyquestions regarding equations and such!
-4(2y)+11y=15, -8y+11y=3y=15: y=5
X=2(5)=10
To check your work -4(10)+11(5)=15
15=15
The answer to this question is 36