Below is an instruction that describes a task. Write a response that appropriately completes the request in Thai. Please answer in Thai.

### Instruction:
Mason is cleaning out all the junk in his attic. 20% of the items are useful, 10% are valuable heirlooms, and 70% are junk. If Marcus's attic has 8 useful items in it, how many junk items does it have?

### Response:
 ห้องเก็บของมี 40 ชิ้นเพราะ 8 / .2 = <<8/.2=40>>40
มีสิ่งของเสีย 28 ชิ้นเพราะ 40 x .7 = <<40*.7=28>>28