Final answer:
To increase the thyme content in the mixture to 40%, we need to calculate how many grams of thyme must be added. We can set up a proportion using the percentages of thyme and solve for the unknown amount of thyme using an equation.
Step-by-step explanation:
To find out how many grams of thyme must be added to the mixture, we can set up a proportion using the percentages of thyme. Let x be the amount of thyme to be added.
The current amount of thyme in the mixture is 25% of the total mixture. So, we have 25% = 0.25. The new amount of thyme in the mixture is 40% of the total mixture, which is 40% = 0.40.
Setting up the proportion, we have (12 + x) / (12 + x + x) = 0.40. Solving this equation will give us the number of grams of thyme that need to be added to the mixture.