Billy sells DVDs. He has 8 customers on Tuesday. His first 3 customers buy one DVD each.  His next 2 customers buy 2 DVDs each.  His last 3 customers don't buy any DVDs. How many DVDs did Billy sell on Tuesday?
His first 3 customers buy 3 * 1 = <<3*1=3>>3 DVDs.
His next 2 buy 2 * 2 = <<2*2=4>>4 DVDs.
He sells a total of 3 + 4 + 0 = <<3+4+0=7>>7 DVDs.
#### 7