Ratio Word Problem Please Explain

Question

You mix 7 tablespoons of vinegar for every 4 tablespoons of baking soda to produce a chemical reaction. You use 15 tablespoons of baking soda. How much vinegar do you use?

Answer 1

15/4 = 3.75 = 3 3/4

3.75 x 7 = 26.25 = 26 1/4 tablespoons of vinegar

You increased baking soda by a factor of 3.75

so you need to increase vinegar by the same factor of 3.75