Acookie recipe states for every three cups of flour,1 teaspoon of vanilla are needed. how many teaspoons are needed for five cups of flour?

For 3 cups... vanilla needed - 1 teaspoon
for 1 cup...vanilla needed- 1/3 teaspoon
for 5 cups, vanilla needed- 5/3 teaspoon

In short , 1.67 or 5/3 teaspoon of vanilla is needed for 5 cups of floor

The answer is 63.!