Problem: what is the max number of rectangular boxes , each measuring 4 inches by 6 inches by 10 inches , that can be packed into a rectangular packing box measuring 16 inches by 18 inches by 30 inches , if all boxes are aligned in the same direction ? 
Options: ['a ) 36', 'b ) 14', 'c ) 12', 'd ) 15', 'e ) 11']
a