Let 
be the volume of 20% solution, 
the volume of the 60% solution. We want a total volume of 400 mL in the final mixture, so
Each mL of either solution will contribute a corresponding concentration, and in the final mixture we want the 400 mL to have a 40% concentration, which means we should also have
Solve the system and we get 
.
Answer:
x=136°
Step-by-step explanation:
x=180°-(180-(46+90))
x=180-44
x=136
Answer:
31.6%
6.67%
14.3%
Step-by-step explanation:
Answer:
x = ±1/2
Step-by-step explanation:
x^2-1/4=0
Add 1/4 to each side
x^2 -1/4+1/4 = 0+1/4
x^2 = 1/4
Take the square root of each side
sqrt(x^2) = sqrt(1/4)
x = ±1/2
