How much water should be added to 75% – salt solution, the mass of which is 1200g. to make the solution 40%?

Let us determine the mass of salt in the initial solution.

To do this, multiply the weight of the solution by the ratio of the percentage of salt concentration in it.

We get:

1200 * 75% / 100% = 1200 * 0.75 = 900 grams of salt.

Find the new weight of the solution after adding water.

To do this, divide the resulting weight of the salt in the solution by the percentage of the new concentration.

Will be:

900/40% / 100% = 900 * 100/40 = 90,000 / 40 = 2250 grams.

Find how much water you want to add.

We subtract the initial weight of the solution from the new weight.

2250 – 1200 = 1050 grams.

Answer:

1050 g of water.