200 g of water was added to 100 g of a 30% salt solution. What is the concentration of the solution?

To find the percentage of the number, you need to multiply this number by the desired percentage and divide by 100.

1) Determine the mass of salt in the initial solution:

100 * 30: 100 = 30 (g) – the mass of salt.

2) Find the mass of the new solution:

100 + 200 = 300 (g) – new solution.

3) Determine the salt concentration in the new solution:

300 g = 100%;

30 g = x%.

Let’s make the proportion:

300: 100 = 30: x;

To find the extreme unknown term of the proportion, it is necessary to multiply the average terms and divide their product by the known extreme term.

x = 100 * 30: 300;

x = 10 (%).

Answer: we got a 10% solution.