Tracy set up a booth at an art fair. 20 people came to look at her art. Four of those customers bought two paintings each. The next 12 of those customers bought one painting each. The last 4 customers bought four paintings each.  How many paintings did Tracy sell at the art fair?
The first 4 customers bought 4*2=<<4*2=8>>8 paintings
The next 12 customers bought 12*1=<<12*1=12>>12 paintings
The last 4 customers bought 4*4=<<4*4=16>>16 paintings
In total Tracy sold 8+12+16=<<8+12+16=36>>36 paintings
#### 36