A couple's wedding reception had 180 people. The bride and groom had each invited 20 couples from their side of the family. The remaining guests were friends. How many friends attended the reception?
How many guests did the bride's side bring? ** From the bride's side, 20 couples * 2 guests/couple = <<20*2=40>>40 guests attended
How many guests did the groom's side bring? ** From the groom's side, 20 couples * 2 guests/couple = <<20*2=40>>40 guests attended
How many friends attended the reception? ** Therefore 180 guests - (40 guests + 40 guests) = <<180-(40+40)=100>>100 friends attended the reception
#### 100