28. A boy decided to cut 10 pieces of wood from a length of wood so tha the first piece was 5cm the second 10cm, the third 15cm, the fourth 20cm and so on until he had cut TO pieces, each one 5cm longer than the one he had cut before. What length of the wood did he use? (a) 50cm (b) 55cm (c) 70cm (d) 200cm (e) 275cm