The sum of the ratio is 1+1+3 = 5, therefore each part is 1500/5 = 300 stickers
Sam got 3 parts for a total of 3*300 = <<3*300=900>>900 stickers
He gave two-thirds of this which is 900*(2/3) = <<900*(2/3)=600>>600 stickers to Andrew
Andrew had one part already, which is 1*300 = <<1*300=300>>300
Andrew now has a total of 300+600 = <<300+600=900>>900 stickers.
#### 900