MANDY ARRANGED 1 FT × 1 FT ×1 FT BOXES IN A STACK THAT IS 5 FT × 5...

9. Mandy arranged 1 ft × 1 ft ×1 ft boxes in a stack that is 5 ft × 5 ft × 5 ft. Andy took all the boxes from the top layer of the stack. Then, Sandy took all the boxes from the rightmost side of the remaining stack. How many boxes are left in the stack?