24. The surface area is 120 m^2 less than its original value.
22. For similar figures, the surface area is proportional to the square of the linear dimension scale factor. Multiplying all linear dimensions by 1/3 will result in reducing the surface area to (1/3)^2 = 1/9 of its original value.
24. As above, the scaled base surface area will be (1/4)^2 = 1/16 of its original value. Since one dimension of the lateral area is multiplied by 4 and the other dimension is multiplied by 1/4, the net effect on that area is multiplication by (1/4)(4) = 1. That is, the lateral area will remain unchanged.
The overall surface area will be reduced by 15/16 of the area of the bases. The area of the bases is (2)(1/2)(8 m)(16 m) = 128 m^2. The changed figure will have a surface area that is 120 m^2 smaller.