A400g solution is 25% salt. how much water must be added to produce a solution that is 40% salt. lots of points

100 grams of salt.

Step-by-step explanation:

First of all, we'll determine our variables:

let x=grams of salt that you already have

let y=grams of salt that need to be added

let z=total amount of salt in the solution after adding salt

We know that salt makes up 25% of the 400g solution, and that 25% can also be written as .25. Thus, we can write an equation to determine x's value:

x=.25*400g

x=100g

Therefore, there are 100 grams of salt already in the solution.

Now that we've determined x's value, we'll bring z into the equation. There are two ways to calculate z. z is equivalent to the sum of x and y. Remember, x is equal to 100 grams. So, z's equation is as follows:

z=100g+y

The other way to calculate z is as a percentage of the final solution. As the question states, we want the final solution to have a salt content of 40% (which we can write as .40). The final amount of solution can be written as below:

400g+y=total amount of solution after adding salt.

This is because we are adding y (the amount of salt needed to bring the salt content to 40 percent)to the amount of solution which we already have.

Therefore, the second way to express z is below:

z=.40*(400g+y)

After we have two equations for z, we can set them equal to each other as follows:

100g+y=.40*(400g+y)

We then can distribute the .40 over the parenthesis.

100g+y=160g+.40y

And then we can subtract 100 grams from both sides of the equation.

y=60g+.40y

Next, we subtract .40 y from both sides of the equation to get y on one side.

.6y=60g

Finally, we can divide both sides by .6 to isolate y.

y=100g

Therefore, you must add 100g of salt to the solution to make it 40 percent salt.

2 apples

step-by-step explanation:

taking away equals subtraction. 6-4=2