Square- 1 1/2
Triangle- 2 1/2
It is four. So two and two you add them together to be four. Good job. Your learning :)
X = the amount of water to add
10 - x = amount of 18% bleach to add
.18(10-x)= .12 x 10
1.8 -.18x =1.2
-.18x = -.6
x = 3 1/3 liters water
therefore 6 2/3 liters bleach