Question #5 tells us that the computer in office 3 was bought in 1988. Let's walk though what this means:
Rule 3 says that the computer in office 3 was bought in the same year as the printer in office 4, so this means that the printer in office 4 was also bought in 1988.
Rule 4 tells us that the computer in office 2 was bought in a different year than the computer in office 3. We know that the computer in office 3 was bought in 1988, so this means that the computer in office 2 was either bought in 1987 or in 1989.
Rule 2 tells us that the computer in office 2 and the printer in office 1 were bought in the same year, so this means that the printer in office 1 was also bought in either 1987 or 1989. However, we can deduce that this printer was bought in 1989 rather than in 1987, because Rule 1 says that the computer in an office is never older than the printer, and the computer in office 1 was bought in 1988. Therefore, both the printer in office 1 and the computer in office 2 were bought in 1989.
This means that the printer in office 2 was bought in 1989, because the computer in the office was bought in 1989 and cannot be older than the printer.
Therefore, the only spot we have left to determine is the computer in office 4, and we can deduce that it was either bought in 1987 or in 1988 because it cannot be older than that office's printer, which was bought in 1988.
This gives us the following setup:
1 2 3 4 C 88 89 88 (87/88)
P 89 89 88 88
Does that make sense? Please let us know if you have any additional questions!
