Alligation method with a ratio twist: Inspired by 
.com
How much 1:25 solution and 1:500 solution should you mix to make a 1L of a 1:250 soaking solution?
:lets convert the ratios into a percent in order to solve the problem with the alligation method:
1:25 (1 / 25= 0.04 X 100= 4%) 1:500 (1 / 500= 0.002 X 100= 0.2%) 1:250 (1 / 250= 0.004 X 100= 0.4%)
1 liter = 1000ml
Now lets do the tic tac toe
_4%____l__________l___0.2%_ / 3.8% X 1000ml= 53ml
l 0.4% l 3.8%
____________________________
0.2% l l 3.6% / 3.8% X 1000ml= 947ml
*The desired % goes in the middle(0.4%), the higher % goes to the left top corner(4%), the lower % goes to the left bottom corner (0.2%).
*Now 0.2% - 0.4%= 0.2% (the 0.2% goes on the right top corner) / Now 4% - 0.4%= 3.6% (the 3.6% goes to the right bottom corner)
*You add both 0.2% + 3.6%= 3.8% (the 3.8% goes in the right middle box)
*Now you do math as I shown on the very top page next to the tic tac toe.
*To know if your problem was correct, simply add both final % and it will equal to the milliliters given in the problem
53 plus 947= 1000ml (1 liter)
