Who lives on the ground floor of the building?

Solution

From 1), Peter lives at floor no 1 or 5 or 7. From 4), Katy is on 4^th floor and he worked for Apple. Now from 5), John lives at floor no. 5 or 6 or 7. Since From 6), it is clear that person who lives in floor  7  worked for eBay and person who lives in floor no 1 worked for Yahoo but not in Monday. So it  is clear that Peter lives at floor no. 5 and John lives at floor no. 6. From 7), Ruby lives at even no. floor. Therefore, the only place left for Ruby is floor no. 2. Hence, Ruby lives at floor no. 2. From 2), one who worked for Starbucks lives immediately above Joseph so that two consecutive floors are floor no. 1 and 2. Therefore, Joseph lives at floor 1 and Ruby worked for Starbucks. Since From 3), one who worked for Google lives on odd number floor above Sarah. So, the only places for Sarah are floor 3. And therefore the only place left for Sam is floor 7 and also from 3), Peter who lives at floor 5 worked for Google. The only Office left for Sarah is Sony, Sarah worked for Sony. From 2), Joseph worked for Yahoo after the day of Thursday that are either Friday or Sunday. But, according to 7), Ruby left 2 days after the one who worked for Sony left. Sarah worked for Sony in Wednesday. Thus Ruby worked on Friday. Katy worked on Thursday.