A 12% brine solution was mixed with a 16% brine solution to produce a 15% brine solution. How much of the 12% solution and how much of the 16% solution were used to produce 40 L of the 15% solution?

10 liters

Step-by-step explanation:

x=12% solution, y=16% solution

x+y=40

0.12x+0.16y=6 .   (12x+16x=600)

-12x-12y=-480

      12x+16x=600

+     -12x-12y=-480

             4x=120

x=30

12% solution= 30 liters

16% solution= 10 liters

infinitely many solutions

step-by-step explanation:

we have been given the equation;

2(2x + 3) = -4 + 2(2x + 5)

we need to determine the value of x.

2(2x + 3), we expand this expression to obtain 4x + 6

similarly 2(2x + 5) will become 4x + 10

now we have;

4x + 6 = -4 + 4x + 10

4x + 6 = 4x + 10 - 4

4x + 6 = 4x + 6

the expression on the left hand side is identical to the one on the right hand side. therefore, we are looking at just a single straight line whose equation is;

y = 4x + 6

consequently, we shall have infinitely many solutions

correct answers below: