Chuck breeds dogs. He has 3 pregnant dogs. They each give birth to 4 puppies. Each puppy needs 2 shots and each shot costs $5. How much did the shots cost? Let's think first. Chain of thought:
He has 3 * 4 = 12 puppies. So they need 12 * 2 = 24 shots. That means the vaccines cost 24 * 5 = $120.
Therefore, the answer is 120.