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?
First find the total number of items in the attic by dividing the number of useful items by the percentage of useful items: 8 items / .2 = <<8/.2=40>>40 items
Then multiply the total number of items by the percentage that are junk to find the number of junk items: 40 items * .7 = <<40*.7=28>>28 items
#### 28