Answer:
9t + 4c ≤ 250
3t + 2c ≤ 80
Explanation:
t is the number of tables
c is the number of chairs
Each table takes 9 hours to assemble and 3 hours to finish, so t tables take 9t hours to assemble and 3t hours to finish.
Each chair takes 4 hours to assemble and 2 hours to finish, so c chairs take 4c hours to assemble and 2c hours to finish.
Therefore, total assembly time is 9t + 4c. Total finishing time is 3t + 2c.
Total assembly time is at most 250, and total finishing time is at most 80.
9t + 4c ≤ 250
3t + 2c ≤ 80