Answer:
To solve this problem, we can set up a proportion:
9.5 cups of flour / 18 cookies = 15 cups of flour / x cookies
To solve for x, we can cross-multiply:
9.5 cups of flour * x cookies = 18 cookies * 15 cups of flour
Dividing both sides by 9.5 cups of flour gives us:
x cookies = 18 cookies * 15 cups of flour / 9.5 cups of flour
x cookies ≈ 28.42
Since we can't make a fraction of a cookie, we'll round down to the nearest whole number. Therefore, Lan can make about 28 cookies with 15 cups of flour using the same recipe.