To solve this problem, we are going to need to set up a proportion. Let's let x represent what we are trying to find, the number of teaspoons of vanilla needed for the cookie recipe when 5 cups of flour are used.
3 cups flour/1.5 tsp vanilla = 5 cups flour/x tsp vanilla
The easiest way to simplify a proportion like this is to cross multiply. This means taking the numerator of one fraction and multiplying it by the denominator of the other fraction and setting it equal to the product of the other numerator and denominator. This is modeled below:
3 * x = 5 * 1.5
The first thing we should do to simplify is multiply our values on both sides of the equation.
3x = 7.5
Next, we should divide both sides of the equation by 3 to get the variable x (what we are trying to figure out) by itself.
x = 2.5
This means that for 5 cups of flour, 2 1/2 teaspoons of vanilla are needed.
Hope this helps!
