How many liters of a 40% acid solution must be added to 12 liters of a 20% solution to obtain a 25% solution

The answer is 4 liters.

Step-by-step explanation:

We want a final 25% solution, which means that the solvent should constitute 25 percent of all the liters of solution.

Let us call the litres of 40% solution, so when they are added to the 12 litres of 20% solution, the total litres of the new solution are:

of these liters, 25% must be the solvent:

Now for the 40% solution, the liters of the solvent are , and for the 20% liter solution, the liters of solve are liters. Thus the total liters of the solvent are

Therefore

see attached

step-by-step explanation:

given the function as;

write the equation replacing f(x) with y

form   and fill a table containing values of y with corresponding values of x

you can take a range for   values of x as -3≤x≤3

solving for x=-3

for x=-2

repeat the same procedure to get the values of y for the remaining ,x=-1 to x=3

plot the values of y against values   of x and obtain the following graph

c

step-by-step explanation: