Your answer would be 6.5. We can vertify this answer by multiplying 8 times 6.5.
I think the incorrect pronoun shift would be the line "<span>before you adopt a pet". I think it should be before one adopts a pet. This is because the sentence started with "It is". The "you" made the sentence very confusing. The second pronoun should be singular, the pronoun you is often denoted as plural and not singular.</span>
Simple and direct, kind of like it sounds. Short and to the point.
Hope this helped!