I am pretty sure that to solve this task we havo to start with: [tex]12 + x = y
12(.30) + 1x = y(.40)[/tex], which makes us go further :
[tex]12 + x = y
3.6 + x = .4y[/tex]
[tex].4(12 + x) = 3.6 + x
4.8 + .4x = 3.6 + x[/tex]
[tex]4.8 - 3.6 = x - .4x
1.2 = .6x[/tex][tex]1.2/.6 = x
2 = x
[/tex]
And it has become clear that the answer is 2 quarts have to be added so that we could have 40%
