This is a 2 part problem. First, we need to find the area of each side, then add them together. (the question isn't asking for volume).
1) The board has six sides(top, bottom, four sides). the top + bottom are 4 by 24 in, the short sides are 2 by 4 inches, and the long sides are 2 by 24 inches. After multiplying, this gives us 96 sq in + 96 sq in for the top and bottom, 8 sq in and 8 sq in for the short sides, and 48 sq in + 48 sq in for the long sides.
2) If we add all of these together, we get 96 + 96 + 8 + 8 + 48 + 48 = 192 + 16 + 96 = 304 sq inches, which is the total surface area.
John brought 20 water melons each water melon cost him 2 dollars. He gave his friend Bob 3/4 of the watermelons. In return bob gave him double the amount of water melons back. How many watermelons does John have now? How much money did he spend on each water melon?