Explanation:
The thickness of each piece of brand A paper is 3 x 10-3 inches. To find the total thickness of all 24 pieces, we can multiply the thickness of one piece by the number of pieces:
Total thickness = (Thickness of one piece) x (Number of pieces)
Total thickness = (3 x 10-3 inches) x (24)
Total thickness = 0.072 inches
Therefore, the total thickness of all 24 pieces of brand A paper is 0.072 inches.