Answer:
4/21 tablespoons of vanilla
Step-by-step explanation:
Let's have the ratios:
- 2/3 tablespoons of vanilla per 3 1/2 dozen cookies
- x tablespoons of vanilla per 1 dozen of cookies
It is solved by cross multiplication as:
- 2/3 × 1 = 3 1/2 × x
- 2/3 = 7/2x
- x = 2/3 ÷ 7/2
- x = 2/3 × 2/7
- x = 4/21
4/21 tablespoons of vanilla needed for 1 dozen of cookies
