Georgia is sick and coughs 5 times a minute.  Her brother Robert is also sick but he coughs twice as much as her.  After 20 minutes, how many times have they coughed?
Robert coughs twice as much as Georgia who coughs 5 times so Robert coughs 2*5 = <<10=10>>10 coughs per minute
Georgia coughs 5 times and Robert coughs 10 times so together they cough 5+10 = <<5+10=15>>15 times per minute
After 20 minutes they will have coughed 15*20 = <<15*20=300>>300 coughs
#### 300