Peter has 20 books. He has read 40% of them. His brother has read 10% of them. How many more of these books has Peter read than his brother?
Peter has read 8 of these books because 20 x .4 = <<20*.4=8>>8
His brother has read 2 of these books because 20 x .1 = <<20*.1=2>>2
Peter has read 6 more books than his brother because 8 - 2 = <<6=6>>6
#### 6