Problem: a block of wood has dimensions 10 cm x 10 cm x 80 cm . the block is painted red and then cut evenly at the 40 cm mark , parallel to the sides , to form two rectangular solids of equal volume . what percentage of the surface area of each of the new solids is not painted red ? 
Options: ['a ) 5.6 %', 'b ) 8.4 %', 'c ) 11.2 %', 'd ) 14.8 %', 'e ) 17.5 %']
a