Answer:
Paul should give 18 teaspoons of medicine to his dog.
Explanation:
It is stated in the question that for every 12 pounds, 3 teaspoons of medicine is to be given to the dog.
This implies that:
12 pounds = 3 teaspoons
1 pound = 3/12 teaspoons
= 1/4 teaspoons ( by cross multiplication )
72 pounds = 1/4 * 72 teaspoons
= 18 teaspoons
Hence, Paul should add 18 teaspoons of medicine to his dog's food.