Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: a man bring 2 cats to his home to eliminate all the mice . they do a half of the work in 5 days , then the man brings 3 more cats . if they hunt at the same rate , how many days will take to hunt all the mice , since the first day ?
7 days
10 days.