Answer: 285
Explanation:
We know that 15 out of 45 dogs are puppies. Let's turn that into a fraction. 15/45. Now we also know that they collect 855 dogs each year, but we don't know how many puppies. The fraction for that would be x/855. (Puppies = X)
Now all we have to do is cross multiply. 15 × 855 is 12825.
12825 ÷ 45 is 285.
So, the number of puppies is 285.