Final answer:
Brenda will need 3 cups of salt if she uses 13 cups of flour in the Play-Doh recipe.
Step-by-step explanation:
To determine how many cups of salt Brenda will need if she uses 13 cups of flour in the Play-Doh recipe, we need to set up a proportion based on the given ratio. The recipe states that for every 2 cups of flour, 1/2 cup of salt is needed. We can write this as 2 cups of flour : 1/2 cup of salt. Since Brenda is using 13 cups of flour, we can set up the proportion as follows:
2 cups of flour / 1/2 cup of salt = 13 cups of flour / x cups of salt
Cross-multiplying, we get 2 * x = 13 * 1/2, which simplifies to 2x = 6. Solving for x, we find that Brenda will need 3 cups of salt if she uses 13 cups of flour.