To solve this question, the user needs to know basic arithmetic and the concept of ratios. The user must also understand that the number of cats and rats is directly proportional to the amount of time it takes to kill a rat.
Let's start by finding the ratio of cats to rats to minutes. From the given information, we know that:
7 cats : 7 rats : 7 minutes
We can simplify this ratio by dividing all three parts by 7:
1 cat : 1 rat : 1 minute
This means that one cat can kill one rat in one minute.