How many grams does a nine percent solution need to be taken to contain 36 g of salt?

To solve this problem, we introduce the conditional variable “X”, through which we denote the required amount of saline solution.

Then, based on the data of the problem, we will compose the following proportion: 9% relate to 36 grams of salt, as 100% relate to X grams of solution.

Then, based on this proportion, we will compose the following equation: X x 9% = 36 x 100%.

Solving this equation, we get X equal to 400 grams.

Answer: the mass of the solution is 400 grams.