21. Lee designed a bookshelf with 6 shelves and a frame. Each shelf weighs 12 pounds.

The frame weighs 38 pounds.

Part A: How much do the shelves weigh altogether? Show your work.

Part B: What is the total weight of the shelves and frame? Explain your reasoning,

6 x 12

72 lbs for the shelves alone, and all together the bookshelf weighs 110 lbs.

Step-by-step explanation:

Step 1: Take the weight of the shelves (12 lbs) and multiply it by the number of shelves total (6), giving us the equation: 6x12 lbs = 72 lbs.

Step 2: take the total weight of the shelves (72 lbs) and add the weight of the base (38 lbs), giving us the equation 72 lbs + 38 lbs = 110 lbs all together.