Question

A cookie recipe states for every 3 cups of flour, 1 1/2 teaspoons of vanilla are needed. How many teaspoons are needed for 5 cups of flour?

Answer 1

3 / 1½ = 2 cups of flour per teaspoon

2x = 5
divide both sides by 2 to isolate x

x = 2.5

You need 2.5 teaspoons of vanilla for 5 cups of flour.