Answer: Your answer would be D
Step-by-step explanation: The reason why is because in the question it said he is already carrying a 20 pound chair. It then say he can carry some boxes that weigh 5 pounds each. The word each is your keyword. With that you can replace the x variable with some single digit numbers. But you also need to make sure your total is less than or equal to 60 pounds. You would pick the less than or equal to sign since he can only carry 60 pounds or less.