2. First measure the side lengths A and B of the bottom of the water tank, add water to the water depth H, and the water depth H is higher than the height of the fruit. Then put the fruit into the water and measure the water depth h 1, and the volume of the fruit is: (h1-h) * a * b.

Iii. 120/4×3=90 cubic decimeter

Fourth, the more contact surfaces of small cubes, the smaller the surface area, and the fewer pages need to be drawn.

According to the arrangement of 2*3*4, the paint is the least, and the surface area is 2*(4*3+4*2+3*2)=52 square decimeters.

According to 1* 1*24 (queuing), most paints are used, with a surface area of 2 * (24 * 1+24 * 1) = 98 square decimeters.