Two weeks are 14 days, so Nathan played for 3 * 14 = <<14*3=42>>42 hours.
Tobias played for 7 days, so he played a total of 5 * 7 = <<5*7=35>>35 hours.
Nathan and Tobias played together for 42 + 35 = <<42+35=77>>77 hours.
#### 77