Ok so I have some questions and not sure if my maths is right, apoligies of this is posted in wrong place. see attachment for diagram of open topped box with dimentions, sorry about poor drawing, units in cm

1. Dirive a mathematical formula for the surface area of box?

My answer :

16 x 48 = 768 x2 = 1,536

16x 64 = 1,024 x2 = 2,048

48x64 = 3,072

add 3 answers = 6,656 cm2 is surface area

2. if each box is cut from 1m squared piece cardboard, how much wastage is there per unit?

10,000 - 6,656 = 3,344com

3. how many boxes can be cut from a ten meter square sheet of cardboard

10,000 x 10 = 100,000 / 6,656 = 15 boxes

can anyone confirm this is correct