A different breakfast cereal is made using only fruit and bran. The ratio of the weight of fruit to the weight of bran is 1 : 3 (b) What fraction of the weight of this cereal is bran?

Volume is length times width times height so
20 times 8 times 30 which is 4,800
surface area is ph (p is perimeter of base), h is height.
so perimeter would be length+length+width+width so 20+20+8+8 which is 56. so multiply 56 times 30 which is 1680. hope this !